Basilica of The National Shrine of The Immaculate Conception

This church is show gorgeous it's worth visiting even if you don't see the Shrine Shop. But if you have time, I'd definitely recommend wandering around the store. They have lots of devotional aids, books on Catholicism, religious art, and the history of the Shrine, as well as cards and souvenirs.

PROS: lots a beautiful artwork
CONS: can be very crowded

This is a beautiful church. It's really pretty heavy on the St. Mary focus, even considering it is a shrine devoted to her. You may also be take aback at the image of Jesus at the head of the church, which really presents him as an imposing physical figure. Below decks you'll find a subterranean catacomb church, which has its own mass schedule. Throughout the basilica you'll also find little tidbits of Catholic history which are quite fasinating. You'll want to devite a good portion of your day to this tour, which you can do yourself or with docents.