Chartres Cathedral

If you can make only one trip, make it this one. Chartres is famous above all for its medieval stained glass, and the deep blues are at their best on a bright morning, when the nave fills with colored light. Entry is free, and the doors are open from 8:30am to 7:30pm all year. Time a visit for a Friday between Lent and All Saints' Day and you can walk the great labyrinth set into the nave floor. Outside, look up at the west front: its two spires do not match, a record of building campaigns centuries apart. The town is about 50 miles southwest of Paris, an easy day out by train.