Its rivers, plunging from well-watered highlands into deep canyons, have hydropower potential.

ECONOMIST: African energy

Mr. BOB SIVINSKI (Program Director, New Mexico Forest Legacy Program): This ranch also has some deep canyons where there's perennial live water, which is really important in this part of New Mexico because this is a very dry area.

NPR: Saving Ranchland from Suburban Sprawl

When scientists used the spacecraft's antennae to analyse radar echoes from the lunar surface, they found that within certain deep canyons near the south pole the echoes increased and were altered in just the way they would be if dirty icerather than rock were filling the caverns.

ECONOMIST: Divining water

We'll go deep into canyons, maybe inside buildings.

FORBES: Robots Of War

The Blue Mountains national park is a World Heritage site and covers a million hectares, with huge cliffs, deep rainforest gulleys, sandstone canyons and waterfalls.

BBC: British tourist falls to death from Australia waterfall

The cap is cut by canyons and troughs that plunge as deep as one kilometre beneath the surface.

BBC: By BBC News Online Science Editor Dr David Whitehouse