La Fuentona Nature · Muriel de la Fuente, Pinares, Soria A karstic spring situated in the districts of Muriel de la Fuente and Cabrejas del Pinar that gives rise to the Abión river and was declared a natural monument on 12 November 1998. It holds Spain's deepest sump: cave divers have descended in it to one hundred metres without yet reaching the end of the gallery. The protected site preserves faunal communities of singular rarity and karstic geological formations among the most extensive in the area. Around it two clearly distinct landscapes stand out: the gorge of the Abión, with abundant vegetation, and the hilltops, with rugged relief and panoramic views. It lies very close to Calatañazor and half an hour from the provincial capital, and the area has several rural tourism guesthouses. Photo: Diego Delso (CC BY-SA 4.0) What to see and do in Muriel de la Fuente