This image shows a stand of Saguaro cacti in the dry mountains surrounding Tucson, Arizona. A star of many Western films the iconic Saguaro cacti are the largest cacti species in the U.S. They can grow upwards to 40 feet tall and typically live 100-200 years. Their bloom is Arizona's state flower. The Saguaro was given its scientific name, Carnegiea gigantic, in honor of industrialist Andrew Carnegie. The Carnegie Institution established the Desert Botanical Laboratory in Tucson in the early 1900's. Location: Tucson , AZ, USA Photographer: Randolph Femmer, USGS