Get in touch with your spiritual side and offer up your own prayer at Parroquia San Marcos. Sit in quiet reflection outside for a while or ask if you are allowed to join the next service.
This Madrid Centro house of prayer is an interesting place to start your day of sightseeing. There's plenty to explore nearby, like Plaza Mayor, Prado Museum, and Santiago Bernabéu Stadium. Take your time at Parroquia San Marcos before heading to these other fine attractions.