The Aalmarkt area in the historical city centre of Leiden is undergoing a metamorphosis. The new Catharinabridge, a 6-meter-wide pedestrian bridge in line with the new Catharina Alley, creates a new circular shopping route. The very slender and fluent appearance of the bridge deck makes the bridge extraordinary. Seen from above the bridge is shaped like an S and the deck is double curved in order to connect well to the street pattern and optimize the smooth traffic flow both on land and on water.