Contrary to what the name suggests, Desierto de los Leones, or Desert of the Lions, is neither a desert nor are there any lions. Rather, it is the name of both Mexico's first national park and the abandoned convent that lies within its forests. 

The origin of the name instead reputedly comes from the forest's remote location outside Mexico City, and because the Spanish settlers were surprised at the number of Puma they encountered in the area, which they called lions. Today, however, things have changed. The Puma has become extinct in the forests, and urban sprawl creeps ever closer.   

These woods were never settled by the Aztecs, who preferred to occupy the lakesides (though there is evidence that they and other earlier civilizations long used the area to hunt deer and other game animals.) It wasn't until the arrival of the Spanish that people began to live in the area in any numbers. In 1606, the Catholic Carmelite order of barefoot monks chose to build their convent here due to its peaceful surroundings and distance from the city, which made it ideal for meditation and retreat. Life for the monks who occupied the building would have been simple but often harsh due to the vow of poverty, silence, and chastity they had taken. In addition to the vow of silence that prohibited the monks from communicating with each other, they also were required to walk barefoot, which must have been very unpleasant considering the terrain, dangers of rattlesnakes and scorpions, and often cold temperatures. 

The convent eventually was abandoned in 1810, partly due to the deterioration and collapse of the building as a result of the near-constant humidity from, as well as the war of independence against Spain reaching the outskirts of the forest. After being used as a military barracks, the area was declared a forest reserve in 1876 and became Mexico's first national park. However, many contend that the monks never really went away, and the convent ruins are surrounded by urban legends about the supernatural. Over the years, many visitors have reported seeing the ghosts of barefooted and hooded monks and feeling the presence of a sinister and unseen entity watching them. 

Though the Puma are gone, plenty of wildlife is still found within the park,  such as coyotes, bobcats, white-tailed deer, raccoons, and foxes. These, however, are seldom to be seen by visitors and it is more likely that you will see reptiles and amphibians such as rattlesnakes, salamanders, and birds of prey like the red-tailed hawk, horned owl, and Harris hawk.