The Muscovites are happy to see the art, but they also came for a more pressing, physical reason: to cool off. "When you come in here, it's just like an oasis," said one museum-goer, Anna.

Moon jellyfish swarm in the cool autumnal waters of a fjord outside Tromsø in northern Norway illuminated by the aurora borealis. Sheltering his equipment in a self-made waterproof housing, Audun used ...