H.R.S. Titanic Memorial Lighthouse
New York, New York
The Titanic Memorial Lighthouse -- really a mini-lighthouse -- once stood on the roof of a Manhattan building. Every day at noon, from 1913 to 1967, the lighthouse's little Times Square-style ball would drop, "activated by a telegraphic signal from the National Observatory in Washington, D.C." according to a plaque bolted to its side.
The plaque does not explain what any of this has to do with the Titanic, although, in fact, the daily ball thing was supposed to serve as a reminder of tragedy. Despite its daily efforts, people forgot, and the lighthouse was turned off and moved to the entrance of the South Street Seaport in 1976.