First adhesive postage stamp of the world was the Penny Black stamp. It was published in the United Kingdom. The first stamp people could buy on 6 May 1840, but it was presented offstage at 5 days before ( 1 May 1840). It contains portrait of Queen Victoria in profile and was in circulation until February 1841.
Features of the Penny Black
total stamps: 68.808.000
cost of a rare stamp (1-5 May 1840, before the official sale): about 5 million US$
In 2015, the 175th anniversary was released many copies of “PB”. I have one. And what about you? 🙂