The eruptions between 1730-1736 created more than 100 volcanoes known as the Montanas del Fuego or Fire Mountains. The last, smaller, eruption was in 1824 and the area remains ‘active’ though ‘dormant’. Nevertheless there is intense heat a few metres below the surface measuring 400-600 degrees centigrade. At the ‘El Diablo’ restaurant at the summit the cooking uses geothermal heat – food is grilled on an iron grid placed above a bore hole through which heat rises.
The craters reveal the strata of the volcanic formations and also the range of colours created by the intense heat.