Factors such as printing errors, limited production, and historical significance all contribute to a stamp’s value. From historic European issues to prized American rarities, here are 10 vintage ...

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

Auction house Director Charles Shreve called Gross' collection, "without question, the most significant and most valuable collection of United States stamps ... that its value comes from the ...