The ramparts of Porta Mosa are the remains of the only existing old gateway to the city, while the other four were demolished in the early 20th century. Porta Mosa is located south-east of the historic center, in an area called Prato del Vescovo. Originally the gate connected the new districts of Prato del Vescovo with the countryside and the small river port of the city, called Le Mose.
Next to the door stands the bulwark of San Giorgio, built starting in 1648 by the French-Piedmontese troops during the Thirty Years' War and ended in 1653. In the 19th century, Porta Mosa fell into oblivion. Closed and abandoned it was not demolished, but with time it deteriorated a lot.
In 1999 the park was renovated and transformed into space for outdoor activities, games and parties. Since then, the park is home to events and concerts during the summer.