For today's Geo Quiz, we patrolled waters off the Arctic coast of Siberia.

We wanted to know the name of the southernmost island of the North Land archipelago.

The answer is: Bolshevik Island.

Captain Alfred McLaren (US Navy) commanded a nuclear submarine that visited Bolshevik Island in 1970.

NASA satellite image of Bolshevik Island

His sub, "the Queenfish," was on a clandestine mission to map thousands of miles of ocean floor in waters the Soviets claimed as their territory. The secret mapping project was in anticipation of possible war in the Arctic.

McLaren recounts the mission in his new book, "Unknown Waters."