San Diego Zoo, San Diego, California
Set across 100 acres of sun-drenched SoCal soil, this zoo is home to more than 3,700 rare and endangered residents, including giant panda bears, as well as an exotic collection of flora and fauna. Animal lovers can even sleep over at this wildlife kingdom, and enjoy an after-hours stroll through the grounds, before retiring to their tents. “A must-see if you visit San Diego,” commented a TripAdvisor traveler. Admission costs $42 for adults (ages 12 and up) and $32 for children (ages three to 11).