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.