Since I first read about this town I've wanted to visit...
Centralia is the least-populated municipality in Pennsylvania, since the local coal mine caught fire under the town back in 1962 - it is still burning to this day.
All real estate in the borough was claimed under eminent domain in 1992 and therein condemned by the Commonwealth of Pennsylvania.
State and local officials reached an agreement with the seven remaining residents on October 29, 2013, allowing them to live out their lives there, after which the rights to their houses will be taken through eminent domain.
More details can be found here: