The 100 Bruggenloop, held in late September in Leiden, centers on a straightforward concept: the longest course involves crossing one hundred bridges. Participants can walk on Saturday or run on Sunday, choosing from 19.5 km, 12 km, and 8 km routes on paved city paths. Runners begin at Stadhuisplein / Vismarkt, while walkers start from Van der Werfpark.
The course winds through Leiden’s historic core, utilizing its bridges, canals, rivers, towpaths, and singels instead of a conventional road course. The main challenge on the long route is the repeated bridge crossings, totaling one hundred ascents and descents within the old city. Along the way, participants will see the nation's oldest university, the Hortus Botanicus, Singelpark, two harbors, city gates, industrial landmarks, and a modern architectural zone. Though the event is relatively new, with only a few editions completed, its unique bridge-crossing theme provides a distinct character without relying on a mountain, trail, or stadium finish.