CHAPTER 1 GOING UNDERGROUND 5 Anna smiled at her brother in the back seat Their car was about to travel through the Laerdal Tunnel in Norway It stretches 15 2 miles 24 5 km The drive from one side to the other takes more than 20 minutes Engineers knew such a long drive in a dark tunnel could make people feel claustrophobic or tired The Laerdal Tunnel links the cities of Laerdal and Aurland in Norway
6 For this reason they designed caverns with colored lights These caverns are every 3 7 miles 6 0 km They are meant to help people stay alert Suddenly Anna's grandfather pulled into a parking bay and the three got out of the car They were standing under a mountain A tunnel is a long narrow path under the ground Tunnels are some of the most challenging projects in engineering and construction Engineers spend a lot of time planning them They must determine a route study the ground and design the excavation method and support Years may pass between the idea of the tunnel and when construction begins
The Romans built this tunnel or cistern to hold water 7 People have been building tunnels for thousands of years Ancient civilizations such as the Incas Aztecs Babylonians and Egyptians all constructed tunnels Engineers in ancient Rome built tunnels too The tunnels carried fresh water into the city and wastewater out
