The Twin Craters (los Gemelos in Spanish) are, in fact, not craters. These impressive holes were formed by magma (lava) domes which hardened on the outside but continued to flow on the inside, leaving huge but empty chambers that collapsed with the passing of time, creating this breathtaking scenery that resembles two pit crates. The Twins are located in the highlands of Santa Cruz Island and are surrounded by lush and green forests, dominated by the endemic Scalesia plants. It is possible to walk along the rim of the craters to better appreciate the magnitude of the holes as well as the local flora and fauna. This site is also one of the most likely places to observe the endemic short-ear owl of the Galapagos.