Set on the site of a medieval mosque, the cathedral now serves as the seat of the Roman Catholic Archdiocese of Madrid. The aim of Madrid's first Catholic cathedral was to overwhelm the believers. Well, the aim has been achieved because the medley of architectural styles is really something exceptional. It houses many interesting paintings as well. The cathedral is also home to a museum which will guide you through the history of Almudena and where you can explore various historical artifacts, such as manuscripts and pieces of clothing. You can also visit a Neo-Romanesque crypt.