When G8 leaders sit down in St Petersburg next weekend, the ground beneath them will silently groan with the weight of the dead. Known as “the city built on bones”, St Petersburg’s foundations sit above the skeletons of the press-ganged slave labourers who toiled to erect it. Historians believe the remains of some 100,000 18th-century serfs are buried beneath its wide Parisian-style avenues and grand Italianate palaces.

Drawn from the length and breadth of the then Russian Empire, they expired from cold, from hunger, from disease, or if they were really unlucky, from the wolves. They gave their lives for the glory of then Imperial Russia and what they created, St Petersburg, stands as a monument to the single-mindedness of the Russian state.

When G8 leaders feast on caviar and quaff champagne, perhaps after discussing debt in the developing world, they are unlikely to spare a thought for the unfortunate slave labourers who built St Petersburg.

They should, for if they want to understand Russia and its complexities, once described by Sir Winston Churchill as “a riddle wrapped in an enigma”, they need look no further than St Petersburg’s incredible history. Its elegant palaces reek of European refinement and were deliberately built in a Western style in an attempt to bring Russia closer to Europe.

But more than three centuries later, it is an odyssey Russia has yet to complete, and St Petersburg is a testament to how difficult that journey has been.