Rome is basically bursting with churches and priceless artwork, but if you have half an hour to see…read moresomething special, spend it at Chiesa di San Luigi dei Francesi, the Church of St. Louis of the French. It's a popular destination in central Rome, near Piazza Navona, free to enter for tourists and worshipers.
We first tried to go when the church was closed, between noon and 2:30 on a Saturday (the hours are posted on the website and worth ascertaining before you visit). When we went back around 3:30, there was a robust line to get in, though it did move pretty quickly. I'd account for a bit of a wait, especially during peak season.
The church has a lovely exterior, the building grand and baroque, completed in 1589. The good stuff, though, is on the inside. The interior is ornate and beautiful, decked out in gold and marble and a small museum's worth of important Italian paintings on the walls and ceiling.
They're all worth looking at, but the main draw is the trio of Caravaggios, a cycle of works about the life of Saint Matthew, painted between 1599 and 1600. You'll know where they are from the crowd gathered in front of the Contarelli Chapel, where the paintings cover the left and right walls and the space above the altar. They are astounding works, easy to appreciate even while standing in a crowd of tourists taking pictures (I obviously took some of my own).
The church has a small gift shop, where you can get prints of the Caravaggios and other souvenirs. We didn't end up buying anything, so this excursion cost us nothing but a meager outlay of our time.
We left Rome with a new appreciation for Italian art, and a special love for Caravaggio. I'm glad we got to see Chiesa di San Luigi dei Francesi, and I fully intend to visit again.