Sant'Ignazio — the church with a dome so convincing nobody realizes it's flat paint on a flat ceiling

The neighbors blocked the dome. Andrea Pozzo's solution (1685): paint one on the FLAT ceiling. Stand on the yellow marble disc in the nave center — your brain sees a dome with columns, windows, and sky. Walk 3 meters off: the illusion collapses. Walk back: dome again. Plus the Apotheosis of St. Ignatius ceiling fresco — the most spectacular ceiling in Rome after the Sistine. FREE.