Flanking Tucson to the east and the west, Saguaro National Park is defined by its vast concentrations of Giant Saguaro cacti, the largest species of cactus in the world. The majestic cacti enjoy a lifespan of from 150 to 200 years and may grow to over 20 feet tall and a weight of over a ton. The park boasts two separate mountain districts with abundant plant life, interpretive hiking trails as well as immense wilderness areas perfect for the prepared backcountry explorer.