El Golfo lagoon | Lanzarote

Green lagoon at El Golfo on the south west coast of Lanzarote north of Playa Blanca.
A volcanic crater was formed during eruptions in the 1730s which was flooded by the ocean. Only half of the cone remains due to sea erosion.
As a result of the flooding, a green colour lagoon was formed due to a combination of algae and sulfur in the water.