Galleria degil Uffizi
The world's greatest haul of Renaissance painting is housed in the ex-offices of the Medici family, a vast U-shaped building located on the Arno. In high season, you will have to stand in line for hours (unless you book tickets in advance), but once inside, the treasures are without equal. You really need a whole day to explore the collection properly, but a couple of hours will allow time to see highlights such as the three Maestà altarpieces by Giotto, Duccio, and Cimabue in Room 2, glowing works from the 14th-century Sienese school in Room 3, and the Masaccio and Masolinos in Room 7. Many make a beeline for the Botticellis in Room 10 (including Primavera and the Birth of Venus) and then leave, but that means missing other masterpieces by Leonardo, Bronzino, Michelangelo, Titian, and Caravaggio. There's a nice rooftop cafe with views over Piazza della Signoria to revive flagging energy.