The Church of San Antonio de los Alemanes is a church in Madrid well-known for its baroque-style interior architecture and the paintings it houses. Located very close to the Gran Vía, this church might look plain on the outside, but what's on the inside will definitely make up for it. Be awed by the sheer number of remarkable paintings, all of which were done in fresco, at each corner of the church. Entrance is free, but you can always make a small donation, which will help in the upkeep of the social soup kitchen next door.