Explore the underground metro
Stockholm’s subway system also doubles as the world’s longest art exhibition, a whopping 68 miles (!!) of paintings, sculptures, mosaics, and more. Of 100 stations, 90 have been converted from drab concrete boxes into amazing works of art. Check it out on a free art walk or at your own pace -- a one-way ticket costs around $3 and, as long as you don’t exit, you can use it the whole way through.
Dine at a milk bar
Eating at a milk bar, a cafeteria serving cheap traditional Polish food, is about as authentic as it gets in Warsaw. As the name suggests, these Communist-era relics are all about dairy, from pierogis dolloped in sour cream to cheese-filled crepes. Bar Prasowy and Bar Mleczny Bambino are both solid choices.