One of my favorite artists that nobody has ever heard of is Tom Russell. He just released his latest album called "Blood and Candle Smoke." It contains a great song he wrote named Guadalupe. It's the story of how he (a non-believer) found himself at the shrine to the Virgin of Guadalupe in Mexico. Below is a youtube clip of Russell singing the song a while back. It's also been recorded by Gretchen Peters.
Russell wrote a blog post with some background on his writing of the song. You can read that here. A warning for the easily offended. Russell is not a believer anymore, so don't go expecting any orthodox opinions. But I do think it shows the power of this Shrine even to a non-believer like him. Plus, I think it's a great song.