The Oude Markt (Old Square) sits one block behind the Grote Markt and occupies a completely different register. Where the Grote Markt impresses with architecture, the Oude Markt impresses with density — it is ringed entirely by cafes and bars, their terraces flowing together into one enormous outdoor space. In term time it is one of the most vivid demonstrations of student culture in Belgium: thousands of young people drinking in the open air, spilling from bench to terrace to pavement.
During the day it's quieter and you can appreciate the square's medieval shape and the mixed facades of the buildings lining it, many of them 17th and 18th century. But the Oude Markt really comes alive at night. The bars range from traditional Belgian cafes serving local Stella Artois and Leuven beers to rougher student spots playing loud music. It's a good idea to spend an evening here — have a beer on the terrace, watch the crowd, and understand why Leuven has a reputation as one of the best student towns in Europe.