Historic communal well, El Pozo de los Frailes, Cabo de Gata Natural Park, Nijar, Almeria, Andalusia, Spain, Europe

Cave system in the Virunga National Park, Rwanda, Africa

The site of the Commandants House showing supports for suspended floor system with hot air to heat rooms above, dating from AD138, Cilurnum (Chesters Roman Fort), Hadrian's Wall, UNESCO World Heritage Site, Chollerford, Northumbria National Park, England, United Kingdom, Europe

Cave system in the Virunga National Park, Rwanda, Africa

Grand Canyon, from Hermit Road, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Bicycles for rent under the Citi Bike system which provides 33000 bikes for rent at 1900 stations, New York City, United States of America, North America

Underwater reef system on pink sand beach, Komodo National Park, Komodo Island, Indonesia, Southeast Asia, Asia

Underwater reef system on pink sand beach, Komodo National Park, Komodo Island, Indonesia, Southeast Asia, Asia

Underwater reef system on pink sand beach, Komodo National Park, Komodo Island, Indonesia, Southeast Asia, Asia

View north of old field system from Carn Llidi, St. Davids, Pembrokeshire National Park, Wales, United Kingdom, Europe

Exposition Park station Metro train, part of Los Angeles's new public transport system, Los Angeles, California, United States of America, North America

Interior of the Baradla-Domica cave system in the Aggtelek National park which stradles the border between Hungary and Slovakia.

Interior of the Baradla-Domica cave system in the Aggtelek National park which stradles the border between Hungary and Slovakia.

Interior of the Baradla-Domica cave system in the Aggtelek National park which stradles the border between Hungary and Slovakia.

Interior of the Baradla-Domica cave system in the Aggtelek National park which stradles the border between Hungary and Slovakia.

Aerial view, industrial park at the harbour, solar panels, Hamm, Ruhr area, North Rhine-Westphalia, Germany, Europe

Windmill and photovoltaic system, Black Forest nature park Park Middle-North, drone recording, Alpirsbach, Baden-Wuerttemberg, Germany, Europe

Windmill and photovoltaic system, Black Forest nature park Park Middle-North, drone recording, Alpirsbach, Baden-Wuerttemberg, Germany, Europe

Solar farm, outdoor plant, solar modules, solar power, Naturpark Altmuehltal nature park, Bavaria, Germany, Europe

Aerial view, industrial complex with companies Lingl, ARO, UTT, photovoltaics, Krumbach, Swabia, Bavaria, Germany, Europe

Solar panels mounted on so called Movers, moving in circles around their axes with the movement of the sun, Gut Erlasee Solar Park, Arnstein, Bavaria, Germany, Europe

Car-Park Routing System, all inner city parking decks are linked, free parking spaces are shown, Essen, North Rhine-Westphalia, Germany, Europe

Solar mirror for heating water, Gokyo, Khumbu, Sagarmatha National Park, Nepal, Asia

Solar panels mounted on so called Movers, moving in circles around their axes with the movement of the sun, Gut Erlasee Solar Park, Arnstein, Bavaria, Germany, Europe

Solar panels mounted on so called Movers, moving in circles around their axes with the movement of the sun, Gut Erlasee Solar Park, Arnstein, Bavaria, Germany, Europe

Historical brine handling system in the Salinenpark park, Bad Rappenau, Neckar, Baden-Wuerttemberg, Germany, Europe

Car-Park Routing System, all inner city parking decks are linked, free parking spaces are shown, Essen, North Rhine-Westphalia, Germany, Europe

Solar panels mounted on so called Movers, moving in circles around their axes with the movement of the sun, Gut Erlasee Solar Park, Arnstein, Bavaria, Germany, Europe

Historical brine handling system in the Salinenpark park, Bad Rappenau, Neckar, Baden-Wuerttemberg, Germany, Europe

The gardens of Alcazar de los Reyes Cristianos, Alcazar of Catholic Kings, Cordoba, Andalusia, Spain, Europe

Solar farm, outdoor plant, solar modules, solar power, Naturpark Altmuehltal nature park, Bavaria, Germany, Europe

Solar Park, outdoor photovoltaic plant, solar modules, solar power plant

Solar farm, outdoor plant, solar modules, solar power, Naturpark Altmuehltal nature park, Bavaria, Germany, Europe

Solar farm, outdoor plant, solar modules, solar power, Naturpark Altmuehltal nature park, Bavaria, Germany, Europe

Solar farm, outdoor plant, solar modules, solar power, Naturpark Altmuehltal nature park, Bavaria, Germany, Europe

Female hiker waits for pack horses to pass on the South Kaibab Trail in Grand Canyon National Park north of Williams, Arizona May 2011. The South Kaibab Trail starts on the south rim of the Colorado Plateau and follows a ridge out to Skeleton Point allowing for 360-degree views of the canyon then down to the Colorado River. At the Colorado River the trail connects with the North Kaibab trail as part of the Arizona Trail system, that crosses the state of Arizona from Mexico to Utah.

Ulster History Park, Omagh, County Tyrone, Ireland

Young Disabled Woman Sitting Beside Her Wheelchair In A City Park In Autumn, Edmonton, Alberta, Canada

Tent And Milky Way Visible In The Sky Over Teton Range, Grand Teton National Park, Wyoming, United States Of America