I toured the USS Becuna, a World War II battleship and the only submarine of its kind left in the world. Take a look inside.

• The USS Becuna submarine sank 3,888 tons of shipping and earned four battle stars in World War II.
• Becuna underwent a Greater Underwater Propulsive Power (GUPPY) 1-A modernization in 1951.
• Now a museum exhibit in Philadelphia, it is the only GUPPY 1-A submarine left in the world.

Built in 1943, the USS Becuna is a Balao-class submarine with a Greater Underwater Propulsive Power, or GUPPY, 1-A modernization — today, it’s the only remaining GUPPY 1-A submarine in the world.

After serving as a battleship in World War II and a training ship after the war, the Becuna was enhanced with a GUPPY 1-A conversion in 1951. The submarine carried out various peacetime missions, such as visiting the Arctic Circle to conduct ice research, and continued to serve as a training ship until it was decommissioned in 1969.

I visited Philadelphia’s Independence Seaport Museum in February to tour the singular submarine with Greg Williams, the museum’s manager of historic ships. Take a look inside.