The Sforza Castle was built in the 15th century by Francesco Sforza, the Duke of Milan, and was the residence of the lords of the city for four centuries. It was one of the biggest citadels in Europe and it is sited along Sempione Park, the largest park in the city.

The original castle was built in the mid 14th century by Galeazzo Visconti, the Lord of Milan, and symbolized the power of the Visconti family. As the family's power declined with the death of Galeazzo, so did the castle. Many battles followed as the Spain, French and German nobles tried to claim title of the castle, but it was Francesco Sforza and the people of Milan who ultimately controlled power and ousted the Visconti family.

Sforza had the original castle rebuilt but wanted to display his power and sophistication so he added a touch of Renaissance to it. He hired a famous Florentine architect known as Filarete to come and build the new fortress. The castle is square-shaped and features four towers at each corner, three courtyards, and a moat.

Leonardo da Vinci spent most of his golden years as an artist at the castle. He contributed to completing many frescoes in a number of the castle's rooms and much of his work portrayed people from the court such as Lady with an Ermine, La Belle Ferronière, and Portrait of a Musician.

Sforza Castle is the largest monument in the city of Milan and second most popular, behind The Duomo. Following an extensive restoration work carried out at the beginning of the twentieth century, it now houses several of the city's museums and art collections.