They want to use the tunnels to take the cars off Amsterdam’s narrow canalside streets to reduce pollution and increase space for cafés, parks and shopping.
The proposal involves draining the biggest canals, digging down 60m to a layer of waterproof clay and dropping in concrete walls. A roof would then be built and the canal water poured back in.
Underneath, up to six storeys of accommodation would be built using access from canalside shafts. Cinemas, for example, could have their entrance at ground level but the auditoria would be in the tunnel.
Since the 1970s more than 30km of tunnels and shopping areas have been built under Toronto, Canada. — Â