Despite being just 2.4 miles apart, the Diomede Islands have a 21-hour time difference between them
The Diomede Islands are made up of Big Diomede, owned by Russia, and Little Diomede, owned by the United States. While only 2.4 miles apart, they sit on opposite sides of the International Date Line, and thus have a 21-hour time difference between them. This is why they are nicknamed Tomorrow and Yesterday Island.