🚀 Inventions and machines 🏗️ Buildings and structures

Tunnels

📖 In short

A tunnel is a passage dug under the ground, through mountains, or under rivers and seas. Cars, trains and people go through it, taking a shortcut instead of climbing the mountain or going round it.

🤩 Did you know?

Some of the biggest machines can dig tunnels 11 meters or more across.
The Gotthard Tunnel in Switzerland is the longest railway tunnel in the world.
Long tunnels have huge fans to bring in fresh air.
Underground water channels in deserts are among the oldest tunnels.

🔎 Find out more

🌟 Giant boring machines

Today engineers dig tunnels with huge machines called “tunnel boring machines”, which have a big spinning head with strong teeth that grind the rock, moving slowly forward and building the tunnel walls behind them.

🔍 Tunnels for everything

There are tunnels for trains, for cars, for metros under cities, for carrying water and sewage, and in mines.

💡 A tunnel under the sea

One of the most famous tunnels is the Channel Tunnel, which runs under the sea between France and England, and trains cross it in about half an hour.

🎯 Ancient tunnels

People have dug tunnels for thousands of years with hand tools, like the ancient Siloam tunnel in Jerusalem for carrying water, and the underground channels of Oman and Iran.