As the westernmost point in North America, Attu is a rugged island dominated by snow-covered mountains (blue in this false-color photo). It is 32 by 56 km (20 by 35 mi) and lies at the far western end of the Aleutian chain, approximately 1770 km (1100 mi) from the Alaskan mainland and 402 km (250 mi) from the Siberian coastline. The weather is characterized by persistently overcast skies, fog, high winds, and frequent cyclonic storms. The Japanese invaded and occupied Attu in June 1942. Today, the island is home to a US Coastguard station and is a sanctuary to many of North America's rarest birds. Image courtesy of NASA.