Almost every medieval city has a Belfry, which is a bell tower, but the belfry of Bruges, or Belfort, is quite a landmark. Maybe it's because it sits in the historical center, or because it is so tall and massive.
Back in the days, the Bruges Belfry had several functions, as it used to house the treasury and the municipal archives, as well as being an observation point for keeping the city safe.
Visitors can get inside, but keep into consideration that there is a narrow, steep, 366 step staircase that goes both ways (in and out). But you can get some panoramic pictures of the city and Bruges Markt from up there. To avoid queues go early in the morning.