Cameron Corner

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

A pair of 19th-century granite markers symbolically record where the state boundaries of New York, New Jersey, and Pennsylvania intersect.

This original Mason-Dixon line cairn placed in the 1760s was put in the wrong location because of the gravitational pull of the Allegheny Mountains.

Despite monuments in other locations, this spot in a South Dakota field is recognized by the U.S. National Geodetic Survey as the center of the 50 states.

A helicopter memorial commemorating what was once the only way to access this West Berlin exclave.

Where Saint-Martin ends and Sint Maarten begins (or vice versa).

A volcanic core jutting above the plain between the Snake and Boise Rivers, a marker identifies the reference point for all U.S. Government Surveys in Idaho.

An iron monument on the 120th meridian as surveyed, one of only four marking the boundary between Nevada and California north of Lake Tahoe.