Pisa is a beautiful, classic Tuscan town. It is famous due to the Leaning Tower of Pisa, which is located in a group of some other beautiful buildings in the Field of Miracles or Square of Miracles.
The Leaning Tower was closed to tourists for years while engineers worked to make it safe to climb. Today, the Italian government actually spends more to keep the tower leaning than it would cost to make it straight. It was recently opened up so you are able to climb to the top. Although you can climb to the top, you'll probably need to be prepared Before You Go in order to have the opportunity. The number of people allowed to climb up per hour is limited, so you'll need to buy tickets. Those tickets tend to sell out fast, but you can buy them in advance Before You Go here.
Climbing the Leaning Tower of Pisa is a fun and unique experience. As you climb the stairs it is abundantly clear which way you are facing because the lean is so extreme that you lean yourself. The steps are all clearly worn to the side of the lean after years of people climbing and having to step in the same place - thanks to gravity and a narrow stairway.
The picture at the left is the view of the Field of Miracles from the top of the Leaning Tower of Pisa.
One thing about Pisa, though, is that there is not a whole lot to see there other than the Field of Miracles. Pisa makes a great 1 day excursion, but if you are going to stay in a city for a few days most people would recommend Florence.