Palazzo Vecchio has been Florence's city hall since 1299. The Salone dei Cinquecento (Hall of the 500) — where the republican council met — is the largest decorated room in Italy: 54m × 23m, ceiling painted by Vasari with 39 panels glorifying Cosimo I, walls depicting Florentine military victories. Behind one of those walls, Leonardo's lost Battle of Anghiari (1505) may still exist — Vasari possibly built a false wall in front of it rather than destroying it. Diagnostic tests in 2012 found pigments consistent with Leonardo's technique behind the plaster. The search continues. Florence museums →
Salone dei Cinquecento: Enter and look UP — Vasari's ceiling (1563-65) with 39 panels in gilt frames. Look at the walls — 6 battle paintings (Florence vs Pisa, Florence vs Siena). Michelangelo's Genius of Victory (marble sculpture, originally intended for Julius II's tomb, unfinished — placed here by Vasari). Studiolo di Francesco I: A tiny windowless room off the Salone — 34 Mannerist paintings concealing secret cabinets where Duke Francesco I kept his alchemical experiments, gemstones, and curiosities. The most claustrophobic and strange room in Florentine art.
Secret Passages Tour (Percorsi Segreti, €18): Book separately — guided tour through hidden staircases, secret rooms, the truss space above the Salone ceiling (you walk ABOVE Vasari's paintings and look down through a spy hole at the hall below), and the athenaeum where Cosimo I's secret documents were kept. Arnolfo Tower (€14 combo): 95m climb (418 steps) — panoramic view of Florence from the medieval tower. The highest public viewpoint in Florence.
Piazza della Signoria. Museum €14, Tower €14, Combo €18, Secret Passages €18 (separate guided tour, book on museicivicifiorentini.it). Open daily 9am-7pm (Thu 9am-2pm). Duration: 1-2 hours (museum) + 30 min (tower). Combine with: Loggia dei Lanzi (outdoor sculpture gallery, FREE, in the same piazza — Cellini's Perseus, Giambologna's Rape of the Sabines) + Uffizi (adjacent — walk through the courtyard).