Here’s a look at some of the 12 most valuable American stamps that are still ... or a pivotal moment in postal history, these stamps are valued not just for their monetary worth but for the ...

An upside down ship makes this commemorative stamp one of the most famous and valuable American postal errors of all. Find ...

The stamp, seen here with Siegel Auctions President Scott Trepel, once famously featured in an episode of the Simpsons A rare US postage stamp ... of the long-running American animated sitcom ...