The massive neo-Gothic building that dominates the skyline above Comillas was built in the 1880s as a Jesuit seminary at the instigation of the Marquis of Comillas, who donated the land and largely funded its construction. The architect was again Joan Martorell, and the result is a grand pile of pointed stone towers and Gothic arches on a commanding hilltop that can be seen from miles along the coast. For a brief period in the late 19th century, Comillas had one of the most prestigious Catholic universities in Spain.
The seminary closed in the 1960s and the building is now used as a conference centre and for summer events. Visitors cannot enter the main building independently, but the exterior is freely visible and worth the short walk up the hill for the views over the town, the coast, and on clear days the peaks of the Picos de Europa inland. The approach road passes through a formal garden that also offers good angles on the building's architecture.