Four days in San Francisco: seven miles square, and none of it flat

Start at the water and climb. This first afternoon covers a mile and a half and about three hundred feet of elevation, and it takes in the three things that make the northeast corner of the city what it is.

The Ferry Building survived the earthquake and fire of 1906 and had a hundred thousand people a day passing through it before the bridges were built, which is hard to picture now. It was gutted and reopened as a food hall, and the stalls under the nave are the best single place to eat in the city on a first afternoon. The farmers' market outside on Saturday mornings is a serious one.

Walk northwest into North Beach, which was the Italian quarter and then the Beat one. City Lights published Ginsberg's Howl in 1956 and got prosecuted for it; the shop is still there, still independent, and still has a room upstairs devoted to poetry with a sign asking you to sit down and read.

Then go up the hill. The wooden stairways on the eastern face are the good way to do it, climbing through hillside gardens and clapboard cottages, and they are steep enough that people stop halfway and pretend to admire the view. Coit Tower at the top was paid for by a woman who spent her life chasing fire engines, and the murals around the inside of the base were painted in 1934 by artists on federal relief. The lift to the top costs a few dollars and is worth it.

The Golden Gate Bridge is the reason a lot of people come, and the mistake is to look at it from a distance and leave. Walk out onto it. The eastern sidewalk is open to pedestrians during daylight, the towers are 227 metres high, and the moment when the first one passes overhead and the deck starts to move slightly under the traffic is the thing photographs cannot do.

Going out about a third of the way and turning back takes an hour and gets you everything. Going the whole mile and three quarters to the Marin side takes closer to two, and there is a bus back.

Then go underneath. Fort Point is a brick coastal fort finished just before the Civil War, tucked directly under the bridge's southern anchorage, and the engineers designed a steel arch over it rather than demolish it. The casemates are open, free and largely empty, and standing in one looking up through the arch at the underside of the bridge is the best ten minutes of the day.

Finish east along the shoreline into the Presidio, which was an army post for two centuries under three flags and is now parkland. The lawns above the old tunnels look straight back at the bridge, there are food trucks parked there most days, and it is a good place to lose an hour.

The big park on the west side of the city is larger than Central Park and was built on sand dunes, which took decades of planting to hold down. It runs four miles west to the ocean, so today stays in the eastern third where everything is, and gets out to a neighbourhood afterwards.

The Academy of Sciences is the standout and it is four museums in one building: an aquarium in the basement, a rainforest under a glass dome, a planetarium and a natural history collection, with a roof planted in seven grass hills that you can walk out onto. Give it three hours and go up to the roof at least once.

Across the concourse, the Japanese Tea Garden is the oldest public garden of its kind in the country, laid out for the 1894 world's fair and kept afterwards. It is small, the entry is a few dollars, and it is worth going in the first hour it opens before anybody else does.

Then take a bus east to Alamo Square in the late afternoon. The row of Victorians on Steiner Street is the most photographed block in the city and it earns it, because the houses are 1890s wooden gingerbread and the financial district towers stack up directly behind them. The light is right after about four o'clock.

The last morning is Nob Hill and Russian Hill, which is the one part of the city where the cable cars are still the sensible way to travel rather than a novelty.

Start at the powerhouse. The cable car museum is the building that actually drives the system: four enormous wheels turning steel cable through channels under the streets at a constant nine and a half miles an hour, with the cars gripping and releasing it. It is free, it is loud, and it makes the whole thing suddenly comprehensible.

Then take the Powell-Hyde line north over Russian Hill and get off at the top of Lombard Street. The famous block has eight hairpin turns and was built that way in the 1920s because the natural gradient was too steep for cars. Walk down it rather than driving it, and photograph it from the bottom, which is where the composition works.

From there it is downhill in every direction. Allow forty minutes to SFO on BART from Powell Street, and more at rush hour.