The largest machine in the world is the Large Hadron Collider, a particle accelerator near Geneva, Switzerland. It has a circumference of 27 km (17 mi). If the Superconducting Super Collider in Waxahachie, Texas, hadn't been canceled in 1993, that would be the world's largest machine, as it had a planned circumference of 87.1 km (54 mi). The Large Hadron Collider is capable of accelerating protons or heavy ions up to 99.9999991% the speed of light, achieving a collision energy of 14 TeV (tera-electron-volts). 14 TeV is about 14 times the energy of a flying mosquito, but packed into a single proton, which is about 1021, or ten trillion billion times less massive than a mosquito.
Despite their very large size, the Large Hadron Collider and other huge particle accelerators are essentially one-dimensional, running around in a relatively thin loop. The largest machine that has a length, width, and height with similar values is the Overburden Conveyor Bridge F60 in Lichterfeld, Germany. This machine is 505 m (1,656 ft) long, 202 m (663 ft) wide, and 80 m (262 ft) high, with a weight of 11,000 tonnes. Built in East Germany by VEB TAKRAF Lauchhammer, the Conveyor Bridge is larger than the Eiffel Tower standing on its side, but was shut down after only 13 months of operation for energy-political reasons. The Overburden Conveyor Bridge is the world's largest machine that can move, but it can only move short distances along its dedicated train tracks.
The Knock Nevis, the world's largest supertanker, is the largest machine that can move long distances. This supertanker is 458 m (1,504 ft) long, 69 m (226 ft) wide, and 30 m (100 ft) tall, with a deadweight (max weight) of 564,763 tonnes, or half a megatonne. This ship operated from 1979 to 2004, now used simply as a floating storage and offloading unit. The ship has such a large draft (portion below the water) that it was incapable of traversing the English Channel. The Knock Nevis would be the world's fourth largest skyscraper if it were a tower.