Museo del Purgatorio (Museum of the Holy Souls)

One of the most genuinely peculiar small museums in Europe — a single glass case inside the Church of the Sacred Heart of the Suffrage (Sacro Cuore del Suffragio) near Castel Sant'Angelo, containing a collection of scorched objects said to bear the handprints, fingerprints, and markings left by souls in Purgatory reaching out to contact the living. Each object — a prayer book, a nightcap, a shirt, a wooden board, a glove — has a documented story of a supposed apparition and the evidence of a burn mark attributed to a soul requesting prayers. The collection was assembled by a French Servite priest, Father Victor Jouët, in the 1890s after a fire in the church left a face scorched onto a wall. Morbid, uncanny, and unforgettable. Featured on TripAdvisor's specialty museums list and mentioned in The Guardian and multiple travel forums as one of Rome's strangest hidden experiences. Free entry.