Fantastic building on the old city side of the river with a wooden lift and interesting architecture. Would not matter if you walked through but we cycled in a circular route through a couple of different tunnels as St Anna's is not the only one but the most interesting.
Walk or bike your way under the Schelde. Wonderfull construction build in 1933, but still working in all it's glory with the original parts, including the wooden elements. Must see!