Saguaro Cactus © Judy Hedding
The biggest saguaros are about 200 years old. They have more than 50 arms. Saguaros can grow to over 50 feet tall, but they are not the largest in the world. There are about 50 varieties of tree-like cacti found in the desert and some of them in Mexico and South America are even taller than the saguaro.