How They Dug the World’s First Tunnel Under a River #history #documentary #architecture #engineering

In 1807, a company tried to dig under the River Thames in London with a narrow, timber-braced shaft. About 200 feet short of the far bank, the river broke in and the tunnel was abandoned. When work started again in 1825, the plan was far bigger: a tunnel 35 feet wide and 20 feet tall, about 75 feet below the high-tide surface, through waterlogged sand and gravel. The answer was an iron shield about 21 feet tall, divided into 36 cells with a worker in each. The face was covered with boards. A worker removed one board, dug out about four inches, and screwed the board back, so there was never more than one small gap. Half the frames dug while the other half were jacked forward, and bricklayers sealed the tunnel with a double brick arch right behind the shield. Floods stopped work for about seven years, but the tunnel opened in 1843, and trains still run through it today. Sources: Royal Museums Greenwich, "Musing on a mollusc: Brunel's inspiration for the Thames Tunnel" Guinness World Records, "First tunnel under a navigable waterway" Grace's Guide, "Thames Archway Co" #shorts #documentary #history #london #thamestunnel #engineering #tunnel #victorian #civilengineering