Santa Maria Novella is one of Florence's beautiful churches. Its location near the train station means that most visitors will pass by it, and probably through the piazza in front of the church, but few take the time to actually go inside. This church deserves at least 30 minutes of your busy travel day because the interior is like a museum. After entering the courtyard to the right of the church facade, you pay about 3 euros to enter and then can walk the interior of the church and visit the cloister, including the frescoed "Green Cloister," in the back.
The pointed and striped Gothic arches of the interior lead you to the front of the church, where Masaccio's Trinity fresco is located. Notice how this innovative Early Renaissance artist used linear perspective (which had just been invented then) to make the scene appear to go back in space. Notice also the eerie inscription of the tomb at the bottom of the fresco, which reads "I was once what you are, and what I am you will become." At the back of the church, don't miss the colorful fresco series in the central Tornabuoni chapel by Renaissance artist Ghirlandaio and his workshop, which included the young Michelangelo. The fresco series gives you hints of what Renaissance clothing and interior design looked like, and the details are beautifully done.
When finished, spend a little time admiring the details of the facade--there are many beautiful designs in the green, pink, and white marble.