New York, Paris, Tokyo, Moscow, Seoul, Beijing, Delhi—more than 150 cities around the world have subways.
A subway is an electric underground railway.
It makes it easy to get around downtown and connects a city to the suburbs.
The oldest subway, and one of the biggest, is the London Tube.
The London subway is called the Tube because its tunnels are narrow and round like a tube.
In fact, its tunnels are the smallest in the world, but the Tube is one of the longest subways, with 391 kilometers of track.
The Tube was the world's first underground rail system.
It was built in 1863. But why did the city of London decide to build a railway underground?
Well, in those days, the streets of London were very busy and dirty!
Back then, the cheapest way to get around town was the omnibus—a horse-drawn bus.
Twenty people could sit inside an omnibus, but it wasn't a pleasant experience.
It was crowded, and there was dirty straw on the floor.
People complained a lot about riding in an omnibus.
So in 1836 the London Times newspaper published suggestions to make the journey more pleasant.
They included: 1. Sit up straight and don't take the space of two people.
2. Do not sit on the straw. You are not in a pigsty.
3. If you have a dog, make sure it is small and has a leash.
4. Do not bring large parcelsㅡan omnibus is not a van.
5. Don't expect the omnibus conductor to have change; he is not a banker.
6. Don't act like you are better than other passengers.
If you can afford to ride a private horse and carriage, then do so!
Riding inside the omnibus may have been bad, but stepping out of the bus and onto the London streets was even worse.
With thousands of horses trotting along, the streets were filled with—you guessed it—horse poo!
The horse dung was so bad that people, often children, worked as crossing sweepers.
Their job was to sweep in front of rich people as they crossed the road.
You can imagine that if people could avoid traveling in the streets, they would!
So when the Tube started in the late 1800s, it was a great success!
Back then, the first Tube carriages were long, narrow, and had no windows.
The Tube's original designers thought there was nothing to see in a tunnel, so why have windows?
By the twentieth century, the Tube had expanded all over London.
During World War I and World War II, Londoners used the Tube stations as bomb shelters.
London was one of the worst-bombed cities during World War II.
People would buy tickets and never come out, because the Tube station was the safest place to be.
From 1939 to 1945, nearly 63 million people stayed in 79 of London's Tube stations.
Restaurants and libraries were set up underground, and performers entertained people.
Even with modern technology, the Tube still has problems.
There's always the danger of flooding from the Thames River.
After giant flood gates were built in 1984, flooding greatly decreased, but some Tube stations still get flooded during thunderstorms.
In the summers it is very hot inside a Tube carriage, and air conditioners can't be installed for two reasons.
First, they give off too much heat, and second, the carriages are too small.
The mayor of London offered a reward of ten thousand pounds for a solution to this problem!
If you ever go to London, make sure you take the Tube!
Look for a round red sign and go down the stairs.
Buy a ticket, wait on the narrow platform, then get on the Tube—and remember you're sitting inside a part of London's history!