Every day for nearly 150 years, on a beach in San Telmo, Panama, a mysterious wreck emerges during low tide. That wreck is the submarine known as Sub Marine Explorer, built by a German inventor between 1863 and 1866. It was one of the first of its kind; hand-powered with a ballast system that would sink or raise the ship at will. Soon its creator got a “fever” and a new engineer took it to the Pearl Islands to harvest oyster shells and pearls. Then he and his crew also caught the same fever, which turned out to be decompression sickness, and the vessel was abandoned in San Telmo.