Pisa

Pisa was a great medieval city, but it was also home to the Renaissance genius, Galileo Galilei. Galileo was born in Pisa, became a professor at the university, and it was a lamp in the Pisa Cathedral, suspended high in the ceiling, that inspired Galileo's experiments with pendulums.

Campo dei Miracoli (Field of Miracles) -
Leaning Tower of Pisa - Don't miss it. A friend writes," I'd expected the Leaning Tower to be a hokey tourist trap, but it was beautiful. The square surrounding the tower was crowded with tourists and local people taking the air. A few guys were having a relaxed pickup soccer game, and they let my son join them for a few minutes." And now, after years of restoration, you can climb up to the top of tower (minimum age for kids is 8 years old).
Duomo (Cathedral) and Baptistery - The Tower of Pisa is really just the bell tower for the Pisa Cathedral. When you step inside the cathedral, look up at that high ceiling and imagine that you're Galileo. The big rounded Bapistery has more of the white marble, inlaid with greenish black marble, a large font in the middle where baptisms were performed, and a gorgeous Pisano marble pulpit with a beautifully carved nativity scene.
Old town walls - The northwest corner of the Campo dei Miracoli is enclosed by sections of medieval town walls. Climb up the medieval tower for good views of all the buildings in the piazza. This tower is free, and there's no age limit, so this is a good alternative if your kids are too little to climb up the Leaning Tower of Pisa.
Walk from the Field of Miracles to the Arno River - What better way to soak up a feeling for this ancient city (Pisa goes back to Etruscan and Roman times) than to walk through the narrow winding streets, lined medieval and Renaissance buildings. Wend your way from the Field of Miracles in the direction of the Piazza dei Cavalieri, then head down toward Pizza Garibaldi on the Arno River.
Take a boat ride on the Arno River - In the Middle Ages, Pisa was a great maritime republic, rivaling Genoa and Venice. Take an hour boat ride on the Arno River, lined with cream, yellow and rust-colored mansions, palazzos, churches and watch towers. There are four stops - near Piazza S. Paolo a Ripa D'Arno, Via Roncioni at the Lungarno Mediceo, Piagge and Renaioli on the outskirts of town (Wherever you pick up the boat, you'll also get off after a full loop trip).
Pisa day trip - If you just want a day on the beach, Viareggio is a resort area, not far from Pisa, with miles of wide sandy beaches. The long promenade has plenty of places to get gelato. Take a walk on the long jetty or run around the pine wood park, Pineta di Ponente.