Southernmost Point Monument, Florida

A concrete buoy monument, installed by the city of Key West in 1983, marks the southernmost point in the continental US that is publicly accessible.  (Technically, it is not the southernmost point–Whitehead Spit is further south, but it is on restricted Navy land, and Ballast Key, a privately owned island, lies even further south.) A webcam broadcasts video from the popular tourist site online, live, 24/7.