This one's a "duh"—the Accademia houses Michelangelo's masterpiece and arguably the world's most famous sculpture, the David. The iconic sculpture was a symbol of Florence long before it held the status it holds today.
The David is the main attraction, of course—prepare to be wowed when you suddenly stumble on it after snaking your way through the first few rooms. It's housed in a custom-built tribune designed in the 19th century. Apart from the David, though, there's a range of Renaissance paintings and even some other sculptures by Michelangelo.
Book ahead so you don't waste time waiting in line!
Su-Sa: 08:15-18:50