$11,628,700 The British Guiana 1c Magenta stands as the world’s most famous rare stamp. Issued in limited numbers in British Guiana (now Guyana) back in 1856, only one specimen exists today. This imperforate stamp is printed in black on magenta paper, featuring a sailing ship alongside the colony’s Latin motto: “Damus Petimus Que Vicissim” (We give and expect in return). Four thin lines frame the ship, and the stamp’s country of issue and value appear in small, black uppercase lettering. Remarkably, it’s the only major postage stamp ever issued within the United Kingdom or British Commonwealth that isn’t part of Britain’s Royal Philatelic Collection. The 1c magenta has a storied history, changing hands from local collector Neil McKinnon to French-born collector Philipp von Ferrary, and eventually being auctioned off for record-breaking sums. (Getty Images)