The Mallos de Riglos are remarkable, almost sheer rock formations in Huesca, forming part of the foothills of the Pyrenees. The rocks are conglomerates and were formed during the Miocene.
Unsurprisingly, these 300-high cliffs are a Mecca for climbers from around the world, and the little village of Riglós nestled improbably below the rocks does a very nice business in accommodating them. However, some of the most demanding routes require spending a free night in a tiny tent strapped to the bare rock face. I suffer from a degree of vertigo and the idea of waking up half way up the sheer face of Los Mallos is one of my all-time favourite nightmares, though I do get a frisson (and a stiff neck) watching those who dare to climb these looming beasts, each of which has its own name; El Puro, El Pisón, Castilla, Volaos, Cuchillo, Frenchín, Visera and Fire.