July 1, 1874
The first US Zoo opens in Philadelphia. Although the Zoological Society of Philadelphia was chartered by the City of Philadelphia many years earlier (March 1859), the Philadelphia Zoo had its grand opening delayed until July 1, 1874 due to the American Civil War. It opened with 1,000 animals and an admission price of 25 cents. For a brief time, the zoo also housed animals brought over from safari on behalf of the Smithsonian Institution, which had not yet built the National Zoo. http://en.wikipedia.org/wiki/Philadelphia_Zoo
A vintage 1950s commercial for the Philadelphia Zoo.
The Philadelphia Zoo celebrated 150 years of success on March 21, 2009.