Georg Heinrich von Langsdorff (1774-1852) was born in Prussia, but was better known by his Russian name, Grigori (Gregory) Ivanovitch, baron of Langsdorff. He was a member of the Academy of Science in St. Petersburg, and was nominated by the consul general of Russia in Rio De Janeiro to lead an expedition from São Paulo to Pará . His nomination received the approval of Czar Alexander in 1821. During the journey the Baron became insane and on his return retired and died in Freiburg, Germany
     The stamp is one of a set issued in 1992 to recognize the UN Conference on Environmental Development in Rio de Janiero.