Like many other Philadelphia landmarks and institutions, the Philadelphia Zoo, located at 3400 West Girard Avenue, is an American first. The charter establishing the Zoological Society of Philadelphia was approved and signed in March 1859. Due to the Civil War, however, it was another 15 years before America's first zoo was ready to open. The zoo opened its gates on July 1, 1874. The Frank Furness Victorian gates and gatehouses, and the zoo's location, are the same today as they were on the day it opened. One of its assets, then and now, is John Penn's home, "The Solitude," which sat on the land chosen for the zoo. John Penn was the grandson of William Penn, founder of Pennsylvania. The Solitude is considered Philadelphia’s most precise and elegant expression of neoclassical style. On opening day, flags flew, and a brass band welcomed more than 3,000 visitors. Admission was 25 cents for adults and 10 cents for children, a rate that held for the next half century. Visitors came on foot, on streetcars, by horse and carriage, and every 15 minutes by steamboat on the Schuylkill River, landing at the zoo's own wharf. The Girard Avenue Bridge opened three days later. As a hub of scientific inquiry and discovery over many years, Philadelphia's well-known leaders of the time began to formulate the idea of a zoo. In the mid-1850s, a prominent Philadelphia physician, Dr. William Camac - the zoo's founding father - became involved and led the way to making America's first zoo a reality. In its first year of operation, the Philadelphia Zoo had 813 animals and received well over 228,000 visitors. Today, the Zoo has more than 1,600 rare and endangered animals comprising nearly 500 different species, and its attendance is approximately 1.1 million visitors a year. The unique Rare Animal House features a variety of animals from around the world. The naked mole-rat, bred right at the zoo; the langur, a leaf-eating monkey; and the little marmoset, are among the many unusual animals to be found here. Most of the animals live in exhibits that approximate their natural habitats. Bears live in Bear Country, which includes a 200,000-gallon pool for polar bears. The South American Exhibit features the highland terrain where anteaters, llamas, capybaras, and others live. Another habitat contains the African Plains' elephants and rhinos, while Australian habitats also are represented, as are the habitats of Pennsylvania at Penn's Woodland Trail. The zoo is home to well over 100 species of birds. The zoo also has a pair of white lions, Jezebel and Vinkel, of which there are probably no more than a dozen in the wild. Carnivore Kingdom, with its jaguar, clouded leopards, and other wonderful beasts, also presents a sad note: a memorial here recalls the tragic fire that struck the Primate House in late 1995. The PECO Primate Reserve, an air-conditioned building, features 10 species of primates including Sumatran orangutans, lowland gorillas, lemurs, langurs, and gibbons. You can watch lemurs romp, spot gibbons and colubus monkeys doing their Monkey See/Monkey Do thing, and the langurs just sitting around.