Is one of the few examples for hydro-volcanism which is explained by an interaction between magma and water. The Golf is a caldera which was affected by the erosion of the ocean parted in the middle. Actually there is a rock in the ocean segregated from the rest of the cone.
Inside the cráter exists a small lagoon known as Laguna de los Clicos which is connected to the ocean by subterranean chasms. It is separated from the ocean by a black sand beach covering parts of the old caldera.
The green colour of the lagoon water due to the huge amount of vegetal organisms existing in there and the special glint and exposure of light depending on the day time and position of the sun give the visitor a feeling of great impression.