Main open-pit copper-sulphur mine at Rio Tinto, Huelva, Southwest Spain, Europe

Main crater of Masaya Volcano caldera, Nicaragua's first national park, its vent is usually shrouded in smoke, Masaya, Nicaragua, Central America

Band-I-Zulfiqar the main lake, Band-E- Amir (Bandi-Amir) (Dam of the King) crater lakes, Afghanistan's first National Park, Bamian province, Afghanistan, Asia

Tourist standing on rock cliff looking at Band-I-Zulfiqar the main lake, Band-E- Amir (Bandi-Amir) (Dam of the King) crater Lakes, Bamian province, Afghanistan, Asia

Poas Volcano, national park in the central highlands of the Alajuela Province, main crater with blue water, sulphur vapour, smoke and clouds, Parque Nacional Volcan Poas, Costa Rica, Central America

Main crater Irazu Volcano with blue crater lake, Irazu Volcano National Park, Parque Nacional Volcan Irazu, Cartago Province, Costa Rica, Central America

Blue crater lake in the main crater of Irazu Volcano, Irazu Volcano National Park, Parque Nacional Volcan Irazu, Cartago Province, Costa Rica, Central America