The Falkirk Wheel is a rotating boat lift that connects the Union and Forth & Clyde Canals in southern Scotland, which are separated by a vertical distance of 35 meters. Until the 1930s, moving from one canal to the other meant going through eleven locks, taking more than a day for each to fill and empty. Then that connection was broken altogether as the canals lost their industrial viability.
The wheel, opened in 2002, takes only a few minutes to raise or lower canal boats most of that vertical distance (there's another, traditional lock in the foreground of these pictures). Because each side of the wheel holds the equivalent of a lock's worth of water, it's so well balanced that it needs only 1.5 kilowatts of power to operate.
Photographs by Jerry Bell.