Short answer Russia's Big Diomede and the US's Little Diomede are 3.8 km apart, yet the date line runs between them and clocks differ by 21 hours.
In the Bering Strait, between Alaska and Siberia, two islands sit side by side.
Big Diomede belongs to Russia and Little Diomede belongs to the US. At the closest point they are only 3.8 km apart.
The International Date Line runs between them. With one line in the middle, the date changes.
21 hoursHow far Big Diomede runs ahead of Little Diomede (20 in summer)
The next island is already tomorrow?
In winter an ice bridge often forms between the islands. The icy waters near the Diomedes, photographed in the early 1900s.
So Big Diomede is nicknamed Tomorrow Island and Little Diomede Yesterday Island.
One step and a whole day passes
Sources
Photo credits
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