Kingman Reef

From Wikipedia:

Kingman Reef is a one-square-kilometer tropical coral reef located in the North Pacific Ocean, roughly half way between Hawaiian Islands and American Samoa at 6°24′N 162°24′W. It is the northernmost of the Northern Line Islands and an unincorporated territory of the United States, part of the United States Minor Outlying Islands, administered from Washington, DC by the U.S. Navy. The reef is closed to the public.

It was found in 1789 by Captain Edmund Fanning of the ship Betsey. Captain W.E. Kingman described it in 1853. It was formally annexed to the United States on May 10, 1922.

Kingman is about 920 nautical miles south of Honolulu.

At times, its shoreline might reach three kilometers in circumference, but the highest point on the reef is about one meter above sea level and wetted or awash most of the time, making Kingman Reef a maritime hazard. It has no natural resources, is uninhabited, and supports no economic activity. The reef partly encloses a deep interior lagoon that was used in 1937 and 1938 as a halfway station between Hawai'i and American Samoa by Pan American Airways flying boats. In 1937, Pan Am had plans to anchor the ship North Wind as a floating tanker at Kingman and use the reef as a stopover for its flying boats on the route to New Zealand but Pan Am abandoned the idea finding the costs of supporting a mostly idle tanker ship prohibitive. There were also concerns that comfortable overnight accommodations would not be available in the event of a mechanical breakdown. As a result, Pan Am switched to Canton Island on May 18, 1939 and began service to New Zealand on July 12, 1940.