Hughes Mining Barge, Floating barge in the USA
The Hughes Mining Barge, also known as HMB-1, is a submersible barge that was originally built for Howard Hughes' Global Marine Development Inc.
It was used in secret CIA operations and played a significant role during the Cold War.
The barge has been featured in several documentaries and films due to its unique design and historical significance.
Today, it is docked at the San Francisco Bay and is not open to the public.
It's one of the few surviving artifacts from Project Azorian, a top-secret CIA operation.
Source: Wikimedia