The Jesuits ran out of money for a dome, so a painter gave them one: on a flat canvas. Here's what you're looking at, and where to stand to see the trick work.
A real dome was planned, but there was no money and neighbors objected that it would block their light. In 1685 Andrea Pozzo painted one on a flat canvas instead, using perspective so precise that it looks real from the right spot.
Pozzo marked the exact point in the nave where his illusion works. From there the painted columns on the ceiling seem to rise straight up into the sky; step away and they start to lean.
Around the edges of the nave ceiling, Pozzo painted Europe, Asia, Africa and America as women, showing the reach of the Jesuits' missions.
No. It's a flat canvas painted by Andrea Pozzo in 1685 to look like a dome.
On the marked disc in the nave, where Pozzo's ceiling perspective works perfectly.
Andrea Pozzo, a Jesuit lay brother, between 1685 and 1694.