Piazza Grande is Montepulciano's main square, sitting at the highest point of the old town and surrounded by some of its best architecture. The Palazzo Comunale, the cathedral, Palazzo Contucci, and Palazzo Nobili-Tarugi frame the space, making it the natural endpoint of the uphill walk through town.
The square is at its best when you take time to look at the facades rather than just pass through. Climb the Palazzo Comunale tower if it is open, then return to the piazza to make sense of the town's hilltop layout.