Certaldo Alto is a quiet walled medieval town, which you can ride up to by funicular from the lower Certaldo.
Visit for beautiful views over Tuscany, lovely architecture throughout the narrow cobbled streets, and many interesting sights for art historians. The town has a certain intellectual heritage as the home of Giovanni Boccaccio, a Renaissance humanist. Dedicated to raising the awareness of culture, he wrote many fine works of prose and poetry. Today there is a small museum and library dedicated to his own works.
Certaldo actually has three museums one ticket gives you entrance to all including a museum of religious art and the Palazzo Pretorio, which you might visit to see the 12th century keep, courtrooms, dungeons, and a chapel with a fresco of Doubting Thomas.