The Scrovegni Chapel is the reason most people come to Padua, and it delivers completely. Beyond Giotto, the city has the Basilica di Sant'Antonio (a major pilgrimage site, architecturally extraordinary), the vast Prato della Valle, the historic Caffè Pedrocchi, and one of the oldest universities in the world still operating from its original buildings. Padua is worth at least a full day, more if you want to explore at a relaxed pace.