International Year of the Periodic Table on cover from Algeria
The Periodic Table of Chemical Elements is one of the most significant achievements in science, capturing the essence not only of chemistry, but also of physics and biology. 1869 is considered as the year of discovery of the Periodic System by Dmitri Mendeleev. 2019 will be the 150th anniversary of the Periodic Table of Chemical Elements and has therefore been proclaimed the "International Year of the Periodic Table of Chemical Elements (IYPT2019)" by the United Nations General Assembly and UNESCO. To mark this event, Algerian Post issued this stamp on 2.1.2019.
There is also two additional definitive stamps on the back, Bordj El Kiffan, issued on 5.8.2015.