During the Cold War, the U.S. built a military base under the ice in Greenland, hidden from the Soviets. It was eventually abandoned, but its most lasting legacy is a pivotal role in climate science.

The American-made Bulldog never saw action at the hands of U.S. tank crews, but it still saw combat. This coming April will mark the fiftieth anniversary of the end of the Vietnam War, and one of the ...