Maastunnel South Ventilation Tower and SS Rotterdam
The tunnel was built from 1937 to 1942. It consists of a set of pre-fabricated tubes that were sunken into a trench that was dug in the river floor. This technique had never been used in Europe before. Two adjacent tubes are for motorised traffic (2x2 lanes). Right next to those there are two stacked tubes. One for pedestrians, on top of which there is one for cyclists. Motorised traffic reaches the tubes via long access roads. Pedestrians and cyclists enter their tunnel from an entirely different location by escalators. Therefore, as a cyclist you could be unaware there even is a tunnel for motorised traffic.
Construction of the tunnel started in 1937. When World War II reached the Netherlands in May 1940, Rotterdam was heavily bombed. The entire historic city centre was wiped flat. However, the tunnel was spared and it was completed during the Nazi occupation. On the 14th of February 1942 there was a secret opening ceremony without Nazi participation.
Prime example of separate cycle infrastructure
The tunnel is a magnificent and early example of elaborate separate infrastructure for cyclists and pedestrians versus motorised traffic. The visible ventilation towers with copper dome roofs are of high architectural quality. With the tunnel they have been a landmark for Rotterdam for almost 70 years now. About 75,000 vehicles and about 4,500 cyclists still use this tunnel daily. In the 1950s a staggering 40,000 cyclists used the four escalators on either side of the tunnel every day. In the morning three were used in the direction of the centre and in the evening it was the other way around. Nowadays there are far less cyclists. Partly due to the decline of cycling in the 1960s and 1970s but also because there are more bridges and tunnels now.
The video shows a ride through the tunnel
The actual bicycle tunnel is 585 meters (640 yards) long and the deepest point of the tunnel is 20 meters (66Ft) below the surface.
After the first bridge in 1878, the Maastunnel was only the second permanent connection across the river. Since the tunnel was built several other bridges and tunnels were constructed. Reducing the importance of this first tunnel. Besides more tunnels for motorised traffic outside the city centre, there are now also a railway tunnel and a metro tunnel. Cyclists wanting to cross the river in the city centre have a choice nowadays between the Maastunnel and two bridges. The 1981 replacement of the original 1878 bridge and the Erasmus bridge aka the Swan from 1996. But they can also use the elaborate regional "waterbus" network. On the waterbus bicycles can be taken for free.
Why this isn't so important as you might think Exceptional infrastructure like this is always interesting to see, but what causes people to cycle in large numbers is the very tight network of everyday, but high quality, cycle routes.