March 25, 1843 — The Thames Tunnel is opened to the public

The Thames Tunnel, connecting Rotherthithe and Wapping, was the first of its kind – the only tunnel up to that point to have been excavated beneath a navigable river. Construction on it began in 1925, by Marc Isambard Brunel and his son Isambard Kingdom Brunel. The two used a new invention created by the older Brunel and his associate Thomas Cochrane, called a tunneling shield. The shield’s purpose is to prevent mud, water or other liquids from flooding the tunnel.

Even with this shield, the tunnelling took years – by the time it finally opened to the public in 1843, after floods and other delays, many had given up on it. But the tunnel proved to be a wonder of its era. It was intended for horsedrawn carriages, but attracted so much pedestrian traffic that it was used solely by pedestrians until 1869. In that year, it was purchased by a railway company and tracks were laid. Services still run through the tunnel today.