Opening of Tower Subway

Date: August 2, 1870 • Location: City of London, United Kingdom

One of the world's earliest underground tube railways opened in the Tower Subway (interior depicted), a tunnel beneath the River Thames in London.

The Tower Subway is a tunnel beneath the River Thames in central London, between Tower Hill on the north bank of the river and Vine Lane on the south. In 1869 a 1,340-foot-long (410 m) circular tunnel was dug through the London clay using a cast iron circular shield independently invented and built by James Henry Greathead, similar to an idea that had been patented in 1864 by Peter W. Barlow but never built.