March 25 -- Marc Isambard Brunel 's Thames Tunnel is opened in London .
Marc Isambard Brunel 's Thames Tunnel is the first tunnel under the River Thames and the world 's first bored underwater tunnel .
March 25 -- Marc Isambard Brunel 's Thames Tunnel , the first tunnel under the River Thames and the world 's first bored underwater tunnel , is opened in London .