Through adverse possession, a landowner can use a neighbor's land long enough and in such a manner as to take ownership of the property. What would be theft in any other context and what is by definition trespass for a period of years translates into the ownership of title to real estate.
The necessary elements of adverse possession, though often repeated, are never clear when applied to the facts. "The use of the land must be open, notorious, visible, exclusive, hostile and continuous such as would apprise a reasonably diligent land owner and the public that the possessor claims the land as his own."
However, the case law chips away at the clarity of each of these elements. "Continous" apparently does not mean uninterrupted in time. "Exclusive" apparently does not mean that others do not use the land.
And now, according to the Wisconsin Court of Appeals, "hostile" and "that the possessor claims the land as his own" apparently does not require the possessor to believe that the land is his own or that he is there without permission.
Wilcox v. Lake Delton Holdings LLC, 2012AP1869 (April 11, 2013)