The Piazza dei Miracoli — tower, duomo, baptistery on a green lawn — is more beautiful than the tower's meme reputation suggests, and the train makes it an easy half-day box-tick. The catch: beyond that one square Pisa is fairly ordinary, the tower-climb tickets sell out, and many visitors feel they've 'done' it in 90 minutes. Worth it as a cheap, iconic half-day; not a full day.