When prospectors converged on San Francisco’s waterfront in the 1840s, eager to find gold, some left their boats in a shallow cove and went off in search of their fortunes. The ships, many in poor shape from the start, began to deteriorate. Some sank. With land at a premium as the city grew, the cove was eventually filled in right over the ships, and some of the owners were able to claim another prize: prime San Francisco real estate. Today, underground streetcars pass through the hull of one ship, and pedestrians in the financial district walk above dozens of boats buried beneath the streets.