Found­ed in 1916, San Diego Zoo hous­es more than 3,500 ani­mals across 650 dif­fer­ent species and has often been award­ed as one of the best zoos in the world. It was also one of the first zoos to have open-air, cage­less exhibits and is sit­u­at­ed in the beau­ti­ful Bal­boa Park.