It was built to mark a fresh start for the country. Peter wanted Russia to be a European power and he commissioned foreign architects to tell that story in stone. These stucco palaces, the canals: they are his legacy.

But the place I want to take you to is this: see? It bursts out of the elegant cityscape like a crazed assertion of Russianness. It’s a luxurious reimagining of a peasant church. The multicoloured onion domes. The headscarved women lighting candles in the nave. The gold glinting on the iconostasis. The mosaics that cover every wall and reflect jewel-coloured light. The incense. At first glance, it seems like the oldest thing in the city, but it wasn’t finished until 1907.

It was consecrated as the Church of the Resurrection of Christ, but most people know it as Spas na Krovi: the Saviour on Blood. Here in the western apse, this canopy (rhodonite, jasper, serpentine) resembles a howdah; perched on four columns, it protects nothing more glamorous than a cobbled floor. Did you ask, why?

*

LET US UNDERTAKE AGAIN the trick of weaving the past from starlight. Set the dial for March 1881. As time spools back around us, indulge me by glancing at two snapshots. First, in 1990, that’s me, wandering around the city, now Leningrad, with a satchel of scavenged brochures. How vulnerable I look. I’m trying to compile information for a guidebook to the Soviet Union – a country that will cease to exist in just over a year. In the lobby of a hotel – beige carpets, marble, one-armed bandits – I fall into conversation with a track-suited tough called Ruslan and his girlfriend, Masha. Ruslan is friendly but somehow on edge. He quizzes me about my job, smokes, fidgets, puts his feet up on the coffee table. After a few minutes, we’re joined by another woman, Natasha, a blonde, who arrives in the elevator from an upper floor and an assignation with a Finnish tourist. She accepts a cigarette from Ruslan and shrugs in answer to Masha’s questioning raised eyebrows. Seated next to me, she smells strongly and incongruously of sweat.

Look: that’s also me, visiting for the first time in 1983, aged fifteen, on a school trip, using my rudimentary Russian to persuade a middle-aged man to buy me a bottle of red wine from the grocery; one more: me hung over on the coach tours of the city, and so clueless that when I got back to London I didn’t know which pictures I’d taken in Leningrad and which in Moscow.