Believe it or no, the largest uninhabited island on Earth is Devon Island in northern Canada. No one can live there because of the climate . . . but scientists can use it to simulate Mars. So its nickname is "Mars on Earth."
There's a city in Alaska called Diomede that's just 2.4 miles away from Russia. It’s not actually on mainland Alaska but is a tiny settlement on the west coast of Little Diomede Island in the Bering Straight. Population was just 93 in 2019.