Christopher Maag wrote a fascinating piece for Credit.com about the little-known legal claim called "adverse possession" that allows people to take possession of abandoned property.
Here’s the basic version of how it works:
1) Someone owns a property, whether it’s a house, a condo or just a strip of ground.
2) If the owner isn’t using the property, somebody else can come in and use it, without the owner’s permission.
3) After some amount of time (in Texas it's three years; in New York State it's ten), the squatter can claim ownership free and clear.
People have been making adverse possession claims for decades. The most famous cases happened on the Lower East Side of Manhattan in the 1980s and '90s, when artists, punks and homeless people squatted in vacant buildings and brownstones.