Who Needs a Tunnel Cities fill up quickly above ground Skyscrapers buildings and roads take up every inch Traffic needs to flow through the city but there is no space for a new road What can they do They can dig underground and build a tunnel This long tube will carry cars and trucks under the city 4 LOADING LOADING LOADING
Traffic is heavy in the city Can a new road underground help 5 LOADING LOADING LOADING
The city decides to build a tunnel YEAR 1 6 LOADING LOADING
Planning a Tunnel Building underground is not easy There are other tunnels under the city already A maze of pipes is under the city Telephone and power lines are hidden underground too Plus there are hard rocks and water So the first step is to study the site Some tunnels in the city are up to 180 feet 55 m below the street 7 LOADING LOADING LOADING
