Also known as the Chicago Zoological Park, Brookfield Zoo is located in the Chicagosuburb of Brookfield, Illions. It houses around 450 species of animals in an area of 216 acres (87 ha). It opened on July 1st 1934, and quickly gained international recognition for using moats and ditches instead of cages to separate animals from visitors and from other animals. The first gorillas exhibited at Brookfield Zoo were a two females that arrived from Africa in October 1936, called Congo and Suzette. Gama, born on November 15th 1969 to parents Alpha* and Omega* was the first baby gorilla ever born here, but she died nine days after birth.
In the 1980s the zoo introduced Tropic World, the first fully indoor rain forest simulation and the then-largest indoor zoo exhibit in the world, on which the gorillas are exhibited currently. The main area where visitors can observe the animals is also indoor, but offers them ample opportunities to climb providing them trunks structures and ropes. It has big windows on the roof to give sun light and visitors can view the gorillas around almost the whole enclosure.