Alex Mustard,Alex Mustard / A view down Nikulasargj Canyon, deep fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates at Thingvellir National Park, Iceland. May 2011. In this photo t...

Alex Mustard / Diver explores the cathedral at Silfra Canyon, deep fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates, at Thingvellir National Park, Iceland. May 2011....

Alex Mustard / A diver explores Nikulasargj Canyona deep fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates at Thingvellir National Park, Iceland. May 2011. In this ph...

Graham Eaton / Sea cliffs, geological section through Cambrian and Ordovician sedimentary rocks with faulted monocline fold structure. Rocks include Nant-pig Musdstones, Abersoch, Gwynedd, Wales, UK

Alex Mustard / The narrow Nes Canyon, a fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates in northern Iceland.

Inaki Relanzon / Fault line between America and Europe at Pingvellir, the first parliament place in the world. Pingvellir National Park, Iceland

Shattil & Rozinski / Aerial view of the San Andreas Fault, California, USA, 1994

Anup Shah / Aerial view of cliffs created by basalt fault line, Great Rift Valley, Kenya

Anup Shah / Aerial view of cliffs created by basalt fault line, Great Rift Valley, Kenya