World’s First Undersea Post Office
According to Christer Brunstrom on the Philatelic Database website, while the post office itself was closed sometime in 1941, there is still today considerable interest in the Sea Floor covers which were mailed to collectors all over the world.
According to Christer, today these covers sell for prices ranging from $30 to as much as $200 on e Bay.
Shown above, a 1940 cover cancelled at the undersea post office in the Bahamas.
For more on the undersea post office, click here.