As a result, the Baden 9 Kreuzer misprint became the most expensive German postage stamp. It is not only German stamp collectors who have a penchant for errors, freaks, and oddities, however.

The only known stamp of its kind, the Alexandria Blue Boy is a circular blue stamp issued in 1847 or 1846 (it’s said to have been used as postage ... is an ultra-rare German stamp printed ...