For Katowice, ul. Mariacka Tylna ('Mariacka rear', which runs parallel to the main ul. Mariacka) is the Mecca of street art in the city.  Here, walking from one end to the other is like an outdoor art gallery, with walls on both sides of the street adorned with everything from murals, and forever changing posters, graffiti and tags. Don't forget to check out the underpass at the beginning of the street.