The Cathedral of Santa María de Regla de León is a temple of Catholic worship, the episcopal seat of the Diocese of León, consecrated under the invocation of the Virgin Mary.

Begun in the 13th century, it is one of the great works of the Gothic style, with French influence. Known by the nickname of Pulchra leonina, which means 'Bella Leonesa', it is located on the Camino de Santiago.

The cathedral of León is known above all for taking the "dematerialization" of Gothic art to the extreme, that is, reducing the walls to their minimum expression to be replaced by colored stained glass, constituting one of the largest collections of medieval stained glass in the world .

Originally, in the current location of the cathedral, the Legio VII Gemina had built some baths, with a size greater than the current building. During the great restoration of the building that took place in the 19th century, its remains were discovered under the cathedral, and in 1996 others were explored along the south facade. Little remains of these primitive buildings, just a few vestiges of mosaics, tegulas and ceramics. Others, like the hypocaust, still remain under the cathedral site.