Why go? Why indeed – you’d think you’d want to avoid this hostile, hard-to-reach Russian zapovednik (strict nature reserve), which remains littered with the detritus of would-be settlers past. But in the summer months, when the daylight is continuous and the melted sea ice permits ships to come close, Wrangel is one of the hottest wildlife tickets in town. Thought to be the last redoubt of the woolly mammoth (which survived here until around 2000 BC), the island is now home to a high density of polar bears (around 350-500) plus reindeer, musk ox and Arctic fox. It’s also beloved of 80,000 Pacific walruses, which gather on the rocks and floes here to breed.

When to go: July-August, when temperatures peak at around 15°C. This is when walruses gather, the island’s 400 plant species burst into life and cruises run.

How to go: Only accessible by very few specialist expedition cruises a year. Voyages leaving Nome (Alaska) may also include the Russian Kamchatka and Chukchi peninsulas.