Walking around the cathedral, walking around here, not many people are here because they need to cross the alleys. The style of the building is beautiful, so it is attracted to stop and enjoy, but it is full of urine smell, which greatly discounts the appreciation. The building has a gothic porch, two floors above the veranda, a series of triple-straight portholes with statues built in 1321, ordered by Milan's consul Visconti, who wants to build a new building near the Palace of Reason to accommodate the city's judicial and notarization activities. The name comes from the Osi family, which owned some palaces in the area before the building was built. The gallery was designed by Scoto of San Gimignano. The main street outside is a shopping street where you can buy and buy.