During the California Gold Rush, hopeful prospectors sailed to California from all around the world. Once they arrived, many sailors, including captains, abandoned their ships, hoping to strike it rich in the goldfields.
Because real estate in San Francisco was at a premium (even back then!), the ships were repurposed as jails, houses, or hotels. Some rotted and sank in the harbor or burned in the fire of 1851. Enterprising speculators just continued building, right on top of the sunken ships.
When digging tunnels for the Bay Area light rail in 1994, crews discovered a fully intact ship, The Rome. Too big to dislodge, they just kept tunnelling, which means the J, K, L, M, N, and T trains travel right through its hull. An estimated 70 ships lie buried under some of the most expensive real estate in the world.
