The Piracés escarpments are strikingly beautiful. They have been forged by the erosive action of the wind in a terrain formed by rocks, sandstone and clay deposits, sediments from the Tertiary Era.

Some of the formations received names like Uncle George or Grandfather Roque, because they looked like an old man wearing a beret. The most spectacular, without a doubt, is the Piedra del Mediodía (the Midday Stone). It is a huge rectangular rock that used to be an Arab castle in the past. The most unique thing about this rock is that the sun’s rays illuminate it at midday, hence, its name.

The Tramaced Serreta, with its eroded sandstones, forms a unique natural scene in La Hoya de Huesca. A small sierra – the serreta – formed by soft sandstone, has been eroded giving rise to cliffs with ledges over 40 m. high with a great many hollows

The Serreta has been catalogued as a ZEPA (special protected area for birds). It has many rock birds of prey, with several pairs of golden eagles, Egyptian vultures, a lot of owls and other birds such as the peregrine hawk, the red-beaked rook, the bee-eater and hoopoes.