Den Anker is a popular upmarket restaurant at the V&A Waterfront that sells a large variety of dishes including super-fresh seafood.
One of the restaurant's most popular traditions is that patrons are required to hand over a shoe as deposit when purchasing one of these beers. This 8.4% Belgian Kwak beer is served in it's traditional round-bottom glass that by accounts is pretty darn expensive to replace, hence the clever shoe-deposit!