The Moses Bridge, Holland

In addition, a bridge was built to access the fort across its moat. The designers felt it would be inappropriate to build a bridge over the moat, so instead, they decided to construct a partially submerged bridge, rendering it practically invisible. The bridge has taken on the name “The Moses Bridge”, as it appears to have divided the moat’s waters. This design (built using Accoya wood) allows people to cross virtually undetected at water level: only a few bobbing heads are usually visible. Its construction is entirely of wood waterproofed with foil.

http://en.wikipedia.org/wiki/Fort_de_Roovere