In 2003, Germany opened a water-filled bridge that lets cargo ships cross over the Elbe River; the 3,012-foot crossing connected two major canals

A ship floating along the river, but not on it, sounds like the setup to a conundrum. That's precisely what happens every day near the German city of Magdeburg, where the Magdeburg Water Bridge carries barges and cargo vessels above the Elbe River in a concrete trough of water. The German Federal Waterways and Shipping Administration (GDWS) says the structure is 918 meters (roughly 3,012 feet) long and is Europe's longest navigable canal bridge. The bridge carries artificial waterways over the river, allowing freight traffic to continue uninterrupted.

Why a bridge over a river was even needed