Trench Bridge, A Pedestrian Bridge Below Water Level
http://youtu.be/f_IVoi4c_88
The Trench Bridge by Dutch architecture firm RO & AD is a pedestrian bridge that is almost entirely below water level. The bridge allows visitors to access Fort de Roovere, a 17th century Dutch fortification surrounded by a water-filled moat.
via Inhabitat
photos via RO & AD