La Caldera de Los Marteles is a recent volcanic structure, and is of freatomagmatic origin. With a depth of some 80 m and a diametre of approximately 550 m, it is the result of an explosive eruption in which lava came into contact with the island’s acuifer waters.
At this point the brightest sun can give way to the thickest fog in a matter of minutes on clear days, caused by the condensation of clouds on the humid windward hillside, transforming it on the downwind side, (called the Föhn, or Foehn effect). The prevailing vegetation is made up of replanted Canary pine trees, highland heather, sage, cerraja plant and the blue tajinaste. At the bottom of the crater lie the geometric patterns of recent farming cultivations.
The landscape surface features many trails and paths etched out of the hillside, which meander in all directions, with glimpses on the northern side of the Roques de Tenteniguada and the well known Roque Grande and, if the tradewinds allow, La Isleta and the city of Las Palmas de Gran Canaria.
This whole territory forms part of the World Biosphere Reserve of Gran Canaria, as declared by UNESCO on 29th June 2005.