Four days in Bangkok: the royal quarter, all of it within one walk

Arrive, drop the bags, and do not attempt anything ambitious. The first afternoon works best as a short climb and a long dinner, both within a couple of kilometres of the old town.

Wat Saket was built outside the old city walls, and for most of the nineteenth century it was where Bangkok cremated its dead: more than sixty thousand plague victims too poor for a funeral were left here. The artificial hill beside it, the Golden Mount, was a failure at first. The chedi built on top under Rama III collapsed into the soft ground, and it took a thousand teak logs under Rama IV to make the mound hold. The chedi that stands there now holds relics of the Buddha found in India and given to Rama V by the British. Three hundred and eighteen steps wind up around it, in shade most of the way, and the terrace at the top is the one place you can see the low old city rather than the towers.

Then south into Chinatown as the light goes. Wat Mangkon Kamalawat is the busiest temple in the quarter, Teochew style, built in 1871, thick with incense smoke and people actually praying rather than photographing. Come out onto Yaowarat Road at seven and the street has changed: the gold shops are shuttered, the food carts are out, and the pavement is a queue.

Be at the palace gate for opening at half past eight. This is not a preference. By eleven the courtyards hold several thousand people and no shade at all, and the difference between arriving at half past eight and arriving at half past ten is the difference between a good morning and a queue.

The Grand Palace was begun in 1782, when Rama I founded the city, and every reign since has added to it, so you walk from pure Ayutthayan temple architecture into Victorian facades with Thai roofs in the space of a few minutes. Inside the walls is the Temple of the Emerald Buddha: a small jade figure high on a gilded pedestal, whose robes the king changes three times a year with the seasons. Shoulders and knees covered, or you will be buying trousers at the gate.

Wat Pho is a ten minute walk south and quieter, partly because everyone has just spent their energy next door. The reclining Buddha fills its hall almost exactly, forty-six metres of brick and gilded plaster, with mother of pearl inlaid into the soles of the feet. The grounds also hold the country's best known school of traditional massage, and an hour on a mat there is the best possible use of the middle of the day.

Then the river. From Tha Tien pier the cross river ferry runs to the Thonburi bank every few minutes for a handful of baht. Wat Arun's central spire is covered in broken Chinese porcelain, set into the stucco so it catches light from every angle, and the steep stairs partway up give you the palace back across the water. Its name means temple of dawn, which is a poor description of when to visit: late afternoon light on that facade is why every photograph of Bangkok looks the way it does.

The modern half of the city, which most visitors write off and should not. Start at Jim Thompson's House, an hour before the tour buses. Thompson was an American who rebuilt the Thai silk trade after the Second World War and then walked into the Malaysian highlands in 1967 and was never found. The house he left is six traditional teak buildings brought in from around the country and reassembled on a canal, filled with the Asian art he collected. Entry is by guided tour only, and the wait in the courtyard can run half an hour, so go early.

Take the middle of the day indoors and cold. Siam is two Skytrain stops away and is essentially a district of air conditioning, which in April is a public service rather than a failure of imagination.

Lumphini Park is best around five, when the temperature drops and half of Bangkok comes out to run, do aerobics in formation and rent pedal boats. Rama VI gave the land to the city as a public park and his statue stands at the south western gate. The monitor lizards in the lake are genuinely large, genuinely wild, and best admired from a few metres away.

Finish at Mahanakhon, twenty minutes' walk or one stop on the Skytrain. The enclosed deck is on the 74th floor of a 314 metre tower; the open rooftop above it has a glass floor at 310 metres that a surprising number of people cannot make themselves walk onto. Time the ticket so you are up there while the light is still going, and stay for the lights coming on.

One last temple, and an early one. Wat Benchamabophit is the newest of the famous ones, built under Rama V in Italian marble with stained glass in the windows, a European hand on a Thai building that somehow works. A cloister behind the main hall holds a collection of bronze Buddha images gathered from across the country and beyond it.

Come at seven or eight and you catch what the temple is actually for: monks line up in front of it to receive food, and people stop on their way to work to give it. It takes twenty minutes and costs nothing.

Then allow far more time for the airport than the map suggests. The Airport Rail Link from Phaya Thai is immune to traffic and the taxi is not, and Bangkok traffic has ended more holidays at the check in desk than any airline.