Charlie Gardner, writing at his blog the Old Urbanist:
Adaptation of old city squares to host parking is very common throughout Europe, and has made occasional appearances in the United States as well. Savannah’s centuries-old Ellis Square, over which a parking structure was built in the 1950s, was recently reconstructed with an underground parking garage. Nashville’s Public Square, which I mentioned last week, now has a multi-story garage beneath it topped by an award-winning green roof.
He also points out that the concept applies to neighborhoods, too.