8Castello Sforzesco and Parco Sempione

Striking from any vantage point, this 15th-century redbrick castle has served as a family residence, military citadel and now museum complex. Leonardo da Vinci designed the defences, and the ramparts still give off an impregnable air, even if the only beings on guard are the feral cats stalking the overgrown moat.  

The tower, completed in 1905, is the work of Luca Beltrami; he honoured the original (which collapsed centuries ago) while still adding his own touches, like the large clock whose radiant sun motif is a riff on the Sforza coat of arms.