Los Gemelos is Spanish for "twin craters," which is exactly what you will find at this destination on Santa Cruz Island. The geological areas of interest were once large underground magma chambers that caved in long ago. Over time, the jungle has overtaken the craters. Only the sheer rocky walls are left as visible volcanic rock, while everything else is covered in a broad variety of trees and flowers.
The short hiking trail can be done as a loop, which in total is less than a mile. Given the short length of the trail and the limited options for viewing when at the craters (you cannot climb down into them), this is a special destination that combines well with other adventures in the area or could be done as a quick stop on your way off the island via the Baltra airport.