Pasaje Russel Arts is a two block long alleyway in the heart of Palermo Soho.
It is one mural after another, making it (and other pasajes in Palermo) a street art hub. Come for a slow walk and take lots of photos. On weekends it's crowded with everyone trying to get the right photo or tik tok or what-have-you but if you go on a weekday you will have the place to yourself.
To learn more about the art you see here, I highly recommend a street art tour like this.