Here are 40 Interesting Tunnel facts.
1-5 Tunnel Facts

1. Downtown Seattle actually sits on top of the original city from the 1800s. It was rebuilt on top of ~20-foot high walled tunnels following a great fire, in order to prevent floods from high tide and sewage. You can go underground to see the original city remnants. – Source
2. Beneath the streets of LA is a complex network of pedestrian tunnels that stretch several blocks. They’ve been used for secret transportation of mobsters, murderers and more than a billion dollars in cash; designated as fallout shelters and homeless shelters and used as backdrops for movies. – Source
3. The oldest subway tunnel in the world has had its only entrance welded shut, and it contains a 100+-year-old steam engine. – Source
4. Due to a compressed air leak, a worker in a subway tunnel under New York City’s East River was blown out of the tunnel, through the mud at the bottom of the river, up through the water, and 25 feet or so into the air. He received no serious injury. – Source
5. In 1963, a man knocked down a wall of his home. Behind it, he discovered a mysterious room and soon discovered an intricate tunnel system with additional cave-like rooms. What he had discovered was the ancient Derinkuyu underground city in Turkey. – Source
6-10 Tunnel Facts

6. In the 70’s South Korea discovered 4 tunnels from North Korea, believed to be incursion routes capable of accommodating 30,000 men per hour. It is believed that there is up to 20 more, undiscovered. – Source
7. There are 30 kilometers of a tunnel underneath downtown Toronto, connecting shops, subway stations and restaurants so people do not need to go outside into the heat and snow. – Source
8. Tokyo is protected from floods by a massive underground system of tunnels and water tanks, with 14000hp turbines that can pump 200 tons of water per second. – Source
9. Russia has approved construction of an estimated $66B tunnel across the Bering Strait starting sometime after 2030, making a Railway from New York to London a possibility during this century. – Source
10. There exist patents for a nuclear-powered drill that heats up the tip of the drill to high enough temperatures to melt rocks and create a glass coated tunnel. – Source
11-15 Tunnel Facts

11. There are hundreds of 1000-year-old underground tunnel systems in Bavaria, and nobody really knows who built them or what they’re for.- Source
12. Missoula, Montana has a whole “underground city” tunnel network that was used for bootlegging and prostitution rings that is still accessible today. – Source
13. Chipmunks build special tunnels in their burrows for pooping. – Source
14. Australia uses giant stop signs projected on sheets of water to prevent tunnel crashes. – Source
15. There are hundreds of nuclear fallout shelters in Switzerland; including a tunnel (roadway) that can be sealed off at both ends to become an underground town that would hold 20,000 people. – Source
16-20 Tunnel Facts

16. The first proposal to tunnel under the English Channel was put forward by a Frenchman in 1802. It would have had illumination from oil lamps, horse-drawn coaches, and an artificial island mid-Channel for changing horses. – Source
17. Lalibela, Ethiopia is home to 11 monolithic churches carved out of mountains and connected by tunnels. The churches’ roofs are at ground level to make them invisible to raiders from a distance. – Source
18. In 1906, after 2 years of digging the Hudson River Tunnel, workers for the Pennsylvania Railroad Company connected Manhattan’s West Side with Weehawken, NJ. They met in the middle of the Hudson, completing the tunnel, and the two ends were only off by 1/16 of an inch. – Source
19. There are 30 foot wide abandoned tunnels behind Niagara Falls. – Source
20. Helsinki is expanding below the surface. Incised into the city’s bedrock are a swimming pool, a shopping area, a church, and a hockey rink. Just to name a few facilities besides 40 miles of tunnels for heating and “parking caverns”. They plan to build 400 buildings until 2020. – Source
There are only 2 pages? Where are the other 20 facts?
within the 2 pages are 40 facts! 🙂