Twenty-one days in the Balkans: Alps at one end, the Acropolis at the other, no flights in between

Start at the crossing in the middle of town. The central span dates from 1842 and became a bottleneck, so in the early 1930s Plecnik added a footbridge on either side and fanned them out, turning a traffic problem into a small stone piazza over the water.

The cathedral a minute east went up between 1701 and 1706, with ceiling frescoes by Giulio Quaglio, but the thing to look at is outside: two bronze doors added in the 1990s, one showing a thousand years of Slovene Christianity and the other six bishops of Ljubljana, cast in heavy relief that people rub until it shines.

Then up the hill, one minute by funicular or twenty on foot. There has been a fort up here since the twelfth century, though most of what stands is fifteenth and sixteenth century rebuilding, and the nineteenth century outlook tower was put up as a fire watch. From the top you get the whole basin, the Sava beyond it and the Kamnik Alps closing the view north.

The market dies by two, so go early. Plecnik built the curving riverside colonnade for it between 1940 and 1942, a double-storey arcade with fish sold in the vaults underneath and a covered walk along the top, and it is the best single thing he made here.

The gallery of Slovene painting across the park is worth an hour even if the names mean nothing: the impressionists of the 1900s painting the same alpine light everybody comes for. It also holds the original of the Robba fountain, brought indoors in 2008 and replaced outside by a copy.

Spend the afternoon in the small round house where Plecnik lived from 1921 until he died in 1957. It is kept as he left it, down to the furniture he designed and the drawings on the table, and a guide takes you round in small groups. It explains the rest of the city better than any museum could.

Two and a half hours across the border on an ordinary train. Croatia joined Schengen in 2023 so the check is a formality, but the guard may still walk the carriages.

Zagreb's old town is two hills. Go up the eastern one first, to the cathedral: neo-Gothic twin spires rebuilt in the 1880s after an earthquake, and damaged by another one in March 2020 that brought a spire down. The scaffolding is now part of the skyline and repairs will take years.

Then cross to the western hilltop for the museum three minutes downhill from the church with the tiled roof. Strangers have donated the objects left over from their failed love affairs, each with a note explaining what it meant, and it began as a travelling exhibition put together by two Zagreb artists after their own break-up. It is funny, then it is not, and nothing else in the country is like it.

Start in the old convent at the top of the upper town, where the city museum runs from the Roman settlement through the Ottoman threat to the socialist decades, with a good section on the 1880 earthquake that produced most of what you walked through yesterday.

Downhill, the archaeological museum holds one genuinely extraordinary object. An Egyptian mummy bought by a Croatian official in the 1840s turned out to be wrapped in linen strips covered in writing, and the writing turned out to be Etruscan: about twelve hundred readable words, the longest surviving text in a language nobody can fully read. It is in a case on the first floor with very little fuss made of it.

In the afternoon take the bus twenty minutes north to the cemetery, which sounds grim and is one of the finest pieces of architecture in the country. It opened in 1876 to a design by Herman Bolle, with long arcades of green domes and ivy, and Catholics, Orthodox, Muslims, Jews and atheists are all buried inside the same walls, which in this part of Europe is worth noticing.

The best rail journey on the route. Six hours south, climbing through the interior, tunnelling under the Dinaric ranges and dropping to the sea for the last hour with the islands lined up offshore. The train ends at the harbour, five minutes from the palace gate and next to the ferry terminal you will leave from in two days.

Walk in through the southern wall straight off the seafront. The first thing you reach is the palace basement, a set of vaulted halls that held nothing but rubbish for centuries and therefore preserved the exact floor plan of the emperor's apartments above. Stairs at the far end bring you up into the courtyard.

This is the centre of the whole thing: a sunken square with granite columns shipped from Egypt down both sides, sphinxes at the corners that were already ancient when Diocletian bought them, and the mausoleum on the east side. People have been standing about in it since 305, and there is a cafe on the steps that puts cushions on the stone.

Be at the cathedral when it opens. It was built as Diocletian's mausoleum, an octagon inside a ring of columns, and consecrated as a church around the seventh century by the people whose faith he had spent his reign persecuting. It carries the name of a bishop he had executed in 304, his own sarcophagus vanished long ago, and it is among the oldest buildings anywhere still working as a cathedral.

Across the narrow lane on the western side of the courtyard is the best preserved Roman room in the complex: a small temple with its original coffered barrel vault, later the baptistery, with a headless sphinx at the door. Ten minutes, and the ceiling is the point.

In the afternoon walk twenty minutes west along the shore to the villa Ivan Mestrovic built for himself in the 1930s, with formal gardens above the sea and the largest collection of his work anywhere. He left Yugoslavia in 1942, gave the house and its contents to the state in 1952 and never came back. The ticket also covers a converted sixteenth century house along the road where he carved a cycle of walnut panels over most of thirty years, and most people miss it.

The fast boat leaves early and takes about four and a half hours, threading between the islands with a stop on the way. It carries foot passengers only, seats are numbered and August sailings sell out, so this is the one ticket to buy weeks ahead.

The berth is at Gruz, twenty minutes by bus from the old town. Come in through the western gate: a stone bridge over a dry moat, a drawbridge that was raised every night for four centuries, and then a sudden drop down steps into the main street.

That street is a single straight limestone canyon polished to a shine, laid out after the earthquake of 1667 flattened almost everything. At the near end stands a domed fountain of 1438 with sixteen spouts, the town end of an aqueduct that brought water from a spring inland and made a siege survivable. All sixteen still run and everybody fills a bottle.

The walls open at eight and the day depends on being there. The circuit is about two kilometres, up to twenty-five metres high and several thick on the landward side, and it takes ninety minutes at a walking pace. There is no shade and no way to turn back, so by late morning it is a single file queue in full sun. At eight it is empty and the roofs are still dark.

The same ticket covers the fort on the rock outside the western wall, built to stop an attack from the sea and from the town itself: the walls facing the city were deliberately left thin so the garrison could never turn on the republic. Over the gate is the line about liberty not being sold for all the gold in the world.

After lunch, two buildings. The palace where the government sat, whose rectors were elected for a single month and were not allowed out of the building during it, which tells you most of what you need to know about how this place stayed independent. And the Franciscan monastery inside the western gate, with a cloister of sixty carved double columns, no two capitals alike, and a pharmacy that has been dispensing since 1317 and still sells hand cream over the counter.

Two and a half hours south with a passport check at the border, since Montenegro is outside the European Union. The road follows every inlet of the bay rather than crossing it, unless the driver uses the short ferry across the narrows, which saves half an hour and is the better ride.

Kotor's old town is a triangle of a few hectares against the base of a cliff, entered through a sea gate with a Venetian lion over it and a date of 1555. Inside, the lanes are so irregular that a map is nearly useless and the squares are named after what used to happen in them: flour, milk, arms, salad.

The cathedral is the oldest thing standing, consecrated in 1166 to a fourth century martyr whose relics were bought here from a passing ship. Two towers, unequal because the money ran out and an earthquake took the rest, and a silver altar screen behind the high altar that a local workshop spent most of a century making. Afterwards, the maritime museum in a baroque palace across the square explains how a bay this small came to run a merchant fleet of three hundred ships.

Start the climb before seven. About thirteen hundred and fifty steps switchback up the cliff inside the fortifications to a fort high above the sea. It takes most people an hour up, there is no shade at all, and by ten on a July morning it is genuinely dangerous. Take more water than you think.

Halfway up, a small church built by survivors of a plague is the natural place to stop and turn around: the town below is a perfect triangle of terracotta and the bay opens out behind it. Above that the path deteriorates and the fort is a ruin, which is fine, because the view is what you came for.

In the afternoon get on the water. Boats run up the bay from Kotor and from the quay at Perast to a small round church on an artificial island. Sailors dropped a rock there after every safe voyage for four hundred years, and sank old ships alongside, until there was enough ground to build on. Inside, the walls are covered in silver offerings from returning crews. The other island fifty metres away is natural, has a Benedictine monastery under cypresses and cannot be landed on, so every boat simply circles it.

The longest road day of the trip and one of the most interesting: five to six hours down the Montenegrin coast past Budva and Bar, over the border, through Shkoder and south across the plain to Tirana. The change once you cross is immediate and hard to describe, and it is the moment this trip stops being a European city break.

Tirana's main square is enormous and was a roundabout until recently. It was repaved as one pedestrian surface in 2017, using stone from every region of the country, and it slopes very slightly up towards the middle so that from any edge you cannot see across it. Skanderbeg is on a horse at one end and the ministries the Italians built in the 1930s run down one side in ochre.

The mosque on the corner is the oldest building on it, finished in 1821. Religion was banned outright in Albania in 1967 and this survived as a cultural monument; it reopened in 1991 when several thousand people walked in without permission and nobody stopped them. The painted interior of trees, waterfalls and bridges is unusual in a mosque and is the reason to go in.

Start underground on the eastern edge of town. A nuclear shelter was cut into the hillside in the 1970s for the political leadership, a hundred-odd rooms on five levels behind a blast door, kept secret until the regime fell. It opened as a museum in 2014 with the rooms as they were, including the leader's own suite, and half of it now holds exhibitions on the occupation, the partisan war and the years that followed. Take a jumper; it is cold in there in August.

Back in the centre, a handsome 1930s villa was built as the country's first maternity hospital and taken over within a few years as an interrogation centre, ending up as the headquarters of the domestic intelligence service until 1991. The rooms hold the bugging equipment, the microphones concealed in furniture and the files they filled, and walking through a listening station room by room is worse than the bunker.

Finish at the strangest building in the country. A concrete ziggurat went up in 1987 as a museum to Enver Hoxha, designed by his daughter and her husband, and spent thirty years as a conference centre, a NATO office, a television studio and a ruin that teenagers slid down. It reopened in 2023 as a technology school, and the steps up the outside are open to anybody.

About four hours east over the hills and across the border, on the line of the Roman road that ran from the Adriatic to Constantinople. The lake appears in the last twenty minutes and it is bigger than you expect: thirty kilometres long, three hundred metres deep in places, and two or three million years old, which makes it one of the oldest lakes on earth.

Get into Ohrid in the late afternoon and go straight to the water. There is a path along the shore from the old town on boardwalks pinned to the cliff, and at the end of it, on a headland of rock with three sides over a drop, stands the small fourteenth century church that everybody has seen photographs of.

Sit outside it and wait. The sun goes down behind the Albanian mountains on the far shore, and this is the quarter of an hour the town is famous for. Afterwards, walk back through the lanes and eat lake fish on a terrace.

Start at the cathedral in the lower town, which is why Ohrid matters. A church has stood here since the ninth century and the building you walk into is largely eleventh, from when this was the seat of an archbishopric governing much of the Balkans. Its frescoes are among the oldest and best preserved in the Orthodox world, and they survived because the Ottomans whitewashed them when it became a mosque. They were uncovered in the 1950s.

Climb from there. Halfway up, a Hellenistic theatre is cut into the hillside, dug out of back gardens in the 1980s and used for concerts in summer; it is the only Greek theatre in the country. At the top are the tenth century walls of the fortress from when a tsar ruled most of the peninsula from this hill. The interior is grass and archaeology and the point is the walk round the ramparts.

Then stop. Fourteen days in, an afternoon in the lake is worth more than another church, and there are ladders and pebble beaches all along the shore below the old town. The water is clear enough to see your feet in five metres of it.

Three hours north through the mountains. Skopje's bus station sits beside the railway station, twenty minutes' walk from the centre or a very cheap taxi.

Go straight to the river. The stone bridge across the Vardar is the hinge of the city, standing on Roman piers and rebuilt in the fifteenth century, and it has been the crossing point ever since. On the southern side is a remade square full of statues and marble; on the northern side, within four paces, the Ottoman town.

The bazaar above the bridge is one of the largest still working in the Balkans: a hill of lanes with mosques on the terraces, jewellers in one street and grill houses in the next, and a covered market that has been on the same spot for five hundred years. Eat here. It is cheap, it is excellent, and it stays busy until late.

Start uphill in the bazaar at the mosque on the terrace, built in 1492 by an Ottoman governor and the finest Islamic building in the country: one wide dome, a courtyard with a fountain and a rose garden, and a view down over the market roofs. It is open outside prayer times and the caretakers are used to visitors.

Above it the fortress walls run along the top of the ridge. Little of the interior survives beyond archaeology and grass, but the walk along the ramparts is the best way to see how the city is arranged: the bazaar tumbling down one side, the river, the marble quarter beyond it and the mountain closing the view south.

Come down through the lanes to the largest of the surviving Ottoman inns, a sixteenth century courtyard with two tiers of arcades built for merchants and their pack animals. It is open, free and usually deserted, and it is the quietest place in central Skopje. Finish in the national museum next door, whose ethnographic floor of regional costume is far better than the building suggests.

The best road leg of the second half. The coach follows the Vardar south through a gorge, out through the last border and onto the plain that Alexander's father ruled. Four hours, one passport check, and the alphabet changes again on the far side.

Thessaloniki gives you Rome first. The emperor Galerius built a palace quarter here around the year 300 and three pieces of it survive in the middle of the modern grid. The arch went up in 303 to mark a victory over the Persians, and its surviving piers are carved from top to bottom with the campaign in horizontal bands. It stands in the road and people walk their dogs past it.

Two minutes north is the brick drum from the same complex, almost as old as the Pantheon in Rome and a smaller cousin of it, which has been a temple, a church with gold mosaics still in the vault, and a mosque whose minaret is still standing outside. Then walk to the water for the Ottoman tower on the front, thirty-four metres of it, once the city prison and now a museum with a spiral ramp to a roof terrace that is where Thessaloniki goes at sunset.

Begin at the basilica of the city's patron, the largest church in Greece, raised in the seventh century over the Roman baths where a young officer was killed for his faith in about 306. It burned in the great fire of 1917 and was rebuilt from its own foundations by 1949, so what you see is honest reconstruction around genuine columns and a handful of surviving mosaic panels. Take the stairs to the right of the altar down into the crypt, which most visitors miss and which is the Roman bath structure itself.

Ten minutes west, the Roman forum sits in a hollow below street level with an odeon, a covered gallery and a small museum in the vaults underneath. It was found by accident in the 1960s when the ground was cleared for a courthouse, which was then built somewhere else.

Spend the afternoon at the museum of Byzantine culture out towards the exhibition grounds. It is arranged as a walk through a thousand years, from early Christian house churches through icons, tomb paintings, jewellery and coins to the fall of Constantinople, and it is exceptionally well laid out. Then eat: the lanes around the covered market are full of small ouzeries where two people order seven plates and stay until closing.

The easiest travel day of the three weeks and the fastest: a modern intercity train doing just over four hours, running the length of Thessaly under Mount Olympus and down into Attica. Reserve a seat, buy a coffee and watch Greece go by.

Athens gives you a soft landing after nineteen days. Walk down from the square in front of parliament in the late afternoon and start with the arch, a marble gateway of about 131 marking where the old Greek city ended and the emperor Hadrian's new quarter began. The inscriptions say exactly that, one on each face, which is a piece of Roman cheek worth reading.

Behind it stand the columns of what was, when it was finally finished, the largest temple in Greece. It was begun in the sixth century BC by a tyrant, abandoned unfinished for six and a half centuries and completed by Hadrian in the same campaign as the arch. Fifteen of its hundred and four columns are standing, and one more lies where a storm dropped it in 1852, in sections, like a stack of coins.

Be at the gate when it opens, which in summer is eight. The site is busiest between ten and one, there is almost no shade on top, and the southern entrance by the museum usually moves faster than the western one the coaches use.

You come up through a monumental marble gatehouse and out onto the plateau, and the first effect is the space rather than the temple: a flat rock the size of a few football pitches standing clear above a city of three million, with mountains on three sides and the sea on the fourth. The great temple was built in fifteen years in the middle of the fifth century BC from marble quarried sixteen kilometres away, and it survived nearly intact as a church and then a mosque until a Venetian shell found the Ottoman powder store inside it in 1687 and blew the middle out. What is happening to it now is a slow, exact reassembly running since 1975.

Then go down to the museum. It stands over an excavated neighbourhood you cross on glass floors, and its top storey is a glass gallery the exact size and orientation of the temple above, holding the surviving sculpture in the order it was carved. Standing in it with the real thing framed in the window is the best hour in Athens and a good place to finish three weeks.

One last morning, and the right thing to spend it on is the low ground north-west of the rock, where the interesting things actually happened: the law courts, the mint, the council house, the shops and the covered walks where Socrates went to annoy people until they executed him for it. It is a green archaeological park now, full of tortoises, and it takes a comfortable ninety minutes.

The temple on the western rise is the best preserved Greek temple anywhere, and the reason is unglamorous: it spent thirteen hundred years as a church, so it kept its roof. Nobody photographs it because it is not on the skyline.

The airport is forty minutes out on the metro from the square in front of parliament, at a flat fare, every half hour. The same line runs the other way to the port at Piraeus if three weeks overland has left you with an appetite for a boat.