Cincinnati's Abandoned Subway

Unknown to many Cincinnatians, sprawling under their feet is a vast network of abandoned and derelict subway tunnels – in fact, the United States’ largest abandoned subway tunnel. Construction of the Cincinnati subway began sometime around 1917, however, just 11 days earlier the United States entered World War I and construction was halted. By 1925 construction slowed to a stop before even half of the proposed 16 mile line was completed. Seven miles between Cincinnati's central business district and the industrial suburb of Norwood were tunneled, bridged, or graded, but no track was laid and no subway cars were ordered. No passengers ever rode between the six stations that were built.

The Incredible Magdeburg Water Bridge in Germany

The Magdeburg Water Bridge is a navigable aqueduct in Germany that connects the Elbe-Havel Canal to the Mittelland Canal, and allows ships to cross over the Elbe River. At 918 meters, it is the longest navigable aqueduct in the world.

The Elbe-Havel and Mittelland canals had previously met near Magdeburg but on opposite sides of the Elbe. Ships moving between the two had to make a 12-kilometer detour, descending from the Mittelland Canal through the Rothensee boat lift into the Elbe, then sailing downstream on the river, before entering the Elbe-Havel Canal through Niegripp lock. Low water levels in the Elbe often prevented fully laden canal barges from making this crossing, requiring time-consuming off-loading of cargo.