It mainly grows in the Andes of central Peru, in harsh conditions and at very high altitudes — above 13,000 feet (4,000 meters).
Maca is a cruciferous vegetable and therefore related to broccoli, cauliflower, cabbage and kale. It has a long history of culinary and medicinal use in Peru.
Maca root has traditionally been used to enhance fertility and sex drive.
It's also claimed to improve energy and stamina.
Note that research on maca is still in its early stages.