The two islands that face each other a day apart

In the middle of the Bering Strait, between Alaska and Siberia, lie the Diomede Islands: Big Diomede, which belongs to Russia, and Little Diomede, which belongs to the United States. Less than four kilometres of water separate them. On a clear day, from the shore of one you can make out the houses on the other.

But the International Date Line runs right between them. The result: Big Diomede is twenty-one hours ahead of its neighbour (twenty in summer). When it is Saturday afternoon on Little Diomede, it is already Sunday on Big Diomede. That is why they are known as Tomorrow Island and Yesterday Isle.

In winter the sea freezes over and, in theory, you could walk from one day into the next in about an hour. In practice it is forbidden: the border is still there even when the ice hides it. During the Cold War, this stretch of sea was known as the Ice Curtain.