Fifty-five acres of Golden Gate Park are given over to this botanical garden, which contains nearly 9,000 plant species from every continent. The collections are organized by region -- you can walk from a California redwood grove to a South American cloud forest to a Southeast Asian magnolia garden in the space of an afternoon.
The garden is a peaceful escape from the city and rarely crowded. San Francisco residents get in free with proof of address. The Mesoamerican cloud forest collection, thriving in the city's cool, foggy climate, is one of the best outside Central America.