The nature reserve of the Acebal de Garagüeta Nature · Arévalo de la Sierra, Almarza, Soria The Acebal de Garagüeta is a protected natural area located in the district of Arévalo de la Sierra, in the north of the province of Soria, within the northern Iberian System and around the Montes Claros mountain range. It is protected as a nature reserve by the Regional Government of Castile and León under Law 11/2008 of 9 December. It is considered the largest holly wood on the Iberian Peninsula and one of the most important in southern Europe: it covers 406.4 hectares, of which some 180 form a pure and continuous mass of holly trees that grow densely and in a maze-like fashion, forming natural vaults traditionally called sestiles, a refuge for thrushes, roe deer and blackbirds, with a microclimate around 5 degrees warmer than outside. Photo: Jonroman (CC BY-SA 3.0) What to see and do in Arévalo de la Sierra