Russia: Catherine & Callum. Catherine's Palace

With the Russian stamps in our passports, we cross the former marshland at the coast near St Petersburg. It's impossibly hot and with record high temperatures and ample humidity, the stunning palaces and museums of St Petersburg, lacking the luxury of air conditioning which we have become too accustomed to, become an intense experience as we wade through the omnipresent crowds, sweltering. When one of the coldest places on Earth hits 90 degrees evening in, evening out, there is little left to the imagination that something is quite clearly wrong with the weather.

I've been here before, to Moscow that is, exactly 20 years back on a snowy September morning when I carried only shorts with me. How different today the weather! Headed to Singapore to conduct research on oil pollution for my graduate dissertation, the national airline of Aeroflot was the cheapest option, except that we weren't informed the flight was an all stopping service, much like a bus, from London to Singapore with every major nation in between.

This is the one city in which we have needed to be accompanied by a guide in the absence of a visa and because I find that experience in itself too limiting for my need to capture the details of the place, I wonder off and am dutifully scolded by the guide and mocked by my fellow passengers ("You're not going to get lost again are you?" "Ha ha") upon my return.

The history of this summer palace in the countryside surrounding St Petersburg arrests me: not just the obvious scale, the distatesful opulence, but the story of its Nazi occupation during WWII. Hollow faces peer out at me from time-stained archive photographs recording the liberation of the palace at the end of the war. In their ghostly, grainy veil, the photos tearfully record the total destruction of the palace's facade, the shelled out interiors gaping to the heavens, the Amber Room, bereft of its namesake which was considered too difficult to remove. Even to this day, restoration of the palace continues.

The Hermitage Museum in St Petersburg left us gasping for air not only from the crowds and overpowering heat but from the weight of 3 million exhibits to contemplate. I am mostly struck by Rembrandt's Danae of 1636 feared lost forever when twice slashed and splattered with acid. 12 years later, the painting was re-hung, the long and painful road to restoration complete. How utterly different too an experience the Hermitage is compared to my London favourites for old masters of the National and Portrait Galleries. I worry about the exposure to such extremes of temperature, such crowds and can only imagine that here at the Hermitage both can do more harm than good.

Here the sun never sets: it's midsummer and when I step out on the decks of the distinguished Disney ocean liner, haze from the nearby nuclear power station glows on the near horizon. The city left a lasting impression, not only for its extraordinary architecture and waterways, but for the pain endured by so many millions, oft forgotten at the end of the war during the 900 day siege of Leningrad. Refusing to surrender, the true horror of the war befell as the approaching army shelled bombs for 18hrs a day in an attempt to literally starve the city to death. And so vain was Hitler in believing he would conquer the city that invitations to the victory celebrations to be held in the city's Hotel Astoria were made.