The concept of real estate, approximately 10,000 years old, tends to bring out the pettiest stubbornness in people, almost raised to a heroic degree. In New York City, there is a tiny triangle set into the sidewalk in front of a cigar store at the corner of Seventh Avenue South at Christopher Street, which is dedicated to an old real estate dispute. David Hess owned land there once, with an apartment building which was condemned to be torn down to make room for the subway. Hess hung onto only this 500 square-inch triangle, which was commemorated with the mosaic. The property was sold after his death in 1938, for the sum of $1000.
At the time of Hess's ownership, it was the smallest piece of real estate in New York.
The legal concept here is "eminent domain", in which a governing entity has the right to simply take over any land within its borders, real estate titles be damned. So for those of you who think you "own" real estate, think again. On the other hand, such policies are necessary to prevent private landowners from seceding from their government to form their own tiny sovereign nation.