Workers on the £14.8 billion Crossrail project say they've now tunnelled under the City of London.
This 1,000-tonne machine called Elizabeth, broke through the eastern end of Liverpool Street's new Crossrail station.
Engineers say the next stop will be Farringdon, which will link all the tunnels for the first time.
The first high-speed trains from west to east London are expected to start running in 2018.
The tunnelling has had to come at a price, with some landmarks loved by Londoners, such as the Astoria in Soho, having to have be demolished to make way for the new high speed service.
Broadcaster Gavin Inskip joined The Evening News to discuss this redevelopment.