The Tucson Mountains lie to the west of Tucson. The tallest mountain is Wasson Peak, at 4,688 feet. These mountains experienced a period of volcanic eruptions over the past two hundred million years. Around 74 million years ago, the volcano underwent an explosive eruption that caused it to collapse into a caldera. This collapse resulted in the formation of megabreccia, which looks like a bunch of volcanic rocks cemented together. Geologists refer to this as Tucson Mountain Chaos, which has given rise to many theories about the origins of the Tucson Mountains. One theory proposes that the Tucson Mountains formed on top of the Santa Catalina Mountains, and during a period of crustal stretching, a detachment fault caused the mountains to slide thirty miles to the west where they currently reside. Wasson Peak was where we get the first appearance of a Tuar Tum when Kandi rides a Thunderbird down to UMC to check on Jeff Kinner.