The St. Louis Zoological Garden, popularly known as the Zoo, was the first of its kind to be operated under a special tax. The City set aside 77 acres of Forest Park for zoo purposes in 1913, state enabling legislation was passed in 1915 and in the following year the plan was approved by the City electorate. Beginning with some bear and monkey cages and the World's Fair bird cage, the Zoo has undergone a systematic development beginning with construction of the old Lion House, followed by the well-known open bear pits in 1919. The Zoo has become world famous for its notable collection of wild life and for its beautiful grounds. It is presently administered by the Metropolitan Zoological Park and Museum District.

A prominent landmark in Forest Park is the Nathan Frank Bandstand located on an island in Pagoda Lake opposite the entrance to the Municipal Opera Theater. It was designed by Helfensteller, Hirsch and Watson and completed in 1925 as a gift from the prominent legislator and philanthropist whose name it bears. The present Field House near the golf course in the park was originally built as a terminal for the Lindell Street Railway Company in 1892 from plans by architects Eames and Young.