The walls are a Venetian architectural creation built by Pallavicino. When control of the city was transferred to Venice, the Venetians sent 15,000 soldiers to protect it from external attacks, and in 1561 the construction of the walls began. To build them, about 250 buildings, 2 churches, and many monuments were demolished, and it took around 50 years to complete. A large sum of money was invested in the walls, which stretch for 6 km and surround Bergamo Alta (Upper Bergamo). Shortly before construction was finished, cannons began to be used, making the walls militarily obsolete, so they remained mainly aesthetic. It is recommended to walk along the walls known as Viale delle Mura, especially between Porta San Giacomo and Parco Sant’Agostino.