This happened just off the dock for the Alcatraz Island ferry in downtown San Francisco. Waters surrounding the city are some of the most great white infested in the world.
On July 26, 1945, the USS Indianapolis reached the island of Tinian, where it delivered the components and enriched uranium necessary for the atomic bomb Little Boy, which would soon devastate Hiroshima. But it's perhaps best known for its role in history's worst shark attack.
Sharks are already scary enough, what with their razory teeth and evolutionarily honed hunting mojo. But this monster has a retractable jaw. A retractable effing jaw. You're welcome, nightmares.