Not just a beautiful church, but also a well-conserved and accessible monastery. There are mummies in the basement crypt, too.
Wikipedia http://en.wikipedia.org/wiki/San_%C3%81ngel#El_Carmen_complex
Address 27 Calle Monasterio, Álvaro Obregón 01790, Mexico
Coordinates 19°20'43.58" N -99°11'21.167" E
