Before exiting Porta San Matteo, the Northern gate, turn right into narrow Via Cellolese, that leads you straight into one of the most interesting squares of the town: Piazza Sant'Agostino.
The small Church of San Pietro is located next to the large building with the Convent of the Augustinian Friars, but it is oriented in the opposite direction. It is one of the most ancient churches in San Gimignano (12th century).
In the middle of the square, between the Church of San Pietro and the Church of Sant'Agostino, next to the convent, there is a hexagonal stone well surmounting a hexagonal base with two steps.