Fun fact most experts consider the US uninvadable: https://en.wikipedia.org/wiki/Invasion_of_the_United_States#...
Long Island, Florida, and Maine invasion by nazi spies swimming to shore from German submarines: https://www.fbi.gov/history/famous-cases/nazi-saboteurs-and-....
Japanese in Attu and Kiska islands in Alaska: https://www.history.com/.amp/topics/world-war-ii/battle-of-t...