Ghost Parking Lot in Hamden, CT.
The owners of the Hamden Plaza shopping center in Hamden, CT commissioned a group in 1978 to bury twenty 1960s and early '70s junker cars (including a Beetle and an open convertible), under asphalt at various depths in the Plaza parking lot.
I live 15 minutes away and remember it well. Unique to say the least, but over time it became a big eye sore. It was finally demolished in 2003.