Chiesa di Sant'Ignazio di Loyola

Famed for two of the most extraordinary trompe-l'oeil paintings ever made, both by Andrea Pozzo (1685-1694). The nave ceiling fresco, The Apotheosis of Saint Ignatius, dissolves the architecture into a riot of saints, angels, and continents soaring up into infinite space — but only resolves correctly from one specific spot, marked by a golden disc on the floor. The dome is even more astonishing: it isn't a dome at all but a painted flat disc, indistinguishable from a real dome until you walk past the marked viewing spot and watch it 'collapse' as the perspective fails. The church was designed for the Roman College and consecrated in 1722. Open until 23:30 — making it one of the few major Roman churches you can visit late at night, when it's most atmospheric.