Drilling through Earth
, January 9, 2014
Engineers stand in front of a Tunnel Boring Machine (TBM) during the breakthrough of a tunnel in Kuala Lumpur on January 9. The world's first variable density TBM has completed the first section of the 9.5 km (5 miles) twin tunnels of the Klang Valley MRT (Mass Rapid Transit) line. Reuters/Samsul Said
