Wrangel Island

Inscribed as a UNESCO World Heritage Site in 2004, Wrangel Island in the Russian Arctic was the last place on the planet where a population of woolly mammoth survived, cut off from the mainland by rising sea levels after the last ice age, until it finally died out barely 4,000 years ago — millennia after the species had disappeared from the rest of the world. It now holds the highest known density of polar bear maternity dens on the planet.