Castellsapera

Castellsapera is a mountain with an altitude of 939.3 meters, standing as the highest and most characteristic peak of the Serra de l'Obac, located within the Sant Llorenç del Munt i l'Obac Natural Park. Situated between the municipalities of Terrassa and Vacarisses (Vallès Occidental), it is a peak included in the popular "100 cims" list by the FEEC.

Geologically, it is a large, elongated monolith primarily composed of Eocene conglomeratic rocks. Its name, "Castell-sapera," derives from its morphology, as its narrow and long rocky summit resembles a large walled castle. Adjacent to it, a distinct rock needle known as the Queixal del Porc stands out.

At the very base of the summit lies the Avenc de Castellsapera, an imposing cave with a 45-meter vertical shaft and a maximum depth of 84 meters. This cave serves as an important hibernation habitat for a significant colony of Schreibers' bats, which is why access to its interior is prohibited between mid-October and mid-May to ensure their protection.

Castellsapera offers a privileged viewpoint dominating the entire l'Obac mountain range. From its narrow, rocky summit, featuring pronounced vertical drops on both sides, spectacular direct views of the Montserrat massif are obtained, as well as of the neighboring peaks of La Mola and El Montcau.

The most common approach is from the l'Alzina del Sal·lari car park up to the Coll de Tres Creus. While the overall hike is accessible, the final ascent to Castellsapera's rock is a narrow path with a considerable slope, requiring the use of hands to scramble up a stone step of almost 2 meters, demanding a certain agility. Regarding climbing, despite having acceptable rock quality and old established routes, climbing is currently totally prohibited due to the natural park's conservation regulations.