Canyons

The crossing takes about 10 minutes if you stop to soak in the panoramic views of the waterfall, the gorge and the river rushing past through the open grating underfoot, or four minutes if you're muttering prayers and hurrying to reach the far side.

Spain's 7 natural wonders were announced in early June 2014 following a public vote

Right in the middle of the Qatar Peninsula, a vast chasm suddenly opens up from the rocky desert, dropping 100 metres into the earth.