The Society for the Protection of the European Bison (SPEB) was founded in 1922 by scientists from Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, the UK, and Sweden

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

. The charity's aims were to conserve and repopulate the European bison, or wisent

Wisent

The wisent , Bison bonasus, also known as the European bison or European wood bison, is a species of Eurasian bison. It is the heaviest surviving land animal in Europe; a typical wisent is about long, not counting a tail of long, and tall. Weight typically can range from , with an occasional big...

, that was then on the brink of extinction. After the last wild wisent was killed in 1927, SPEB reintroduced wisents (from collections in zoo

Zoo

A zoological garden, zoological park, menagerie, or zoo is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred....

s) back into the wild in the Bialowieza Forest

Bialowieza Forest

The Belovezhskaya Pushcha / Białowieża Forest, in Belarus and Puszcza Białowieska in Poland, is an ancient woodland straddling the border between the two countries, located north of Brest and south-east of Białystok...

 of Poland, where they still exist, as critically endangered species.