I had the good venture of spending my high school years in Rome, just at the time when you get acquainted with the fine arts. My memories are still vivid with entering the churches of San Luigi dei Francesi and Santa Maria del Popolo and seeing the Caravaggios in there.
They are an unforgettable sight. They hang high up, far out of reach, and you have to drop a coin to turn on the lights that allow you to see them. And when you do, get ready for them, because they are not what you'd expect in a church.
Caravaggio's paintings are spectacular in a way you can't readily appreciate, because they are so contradictory. They are vulgar in their depictions of the commonest things, and yet sublime. They are photorealistic, yet give up any pretension of accuracy when even major positional problems face the painter with the ugliness of reality.