The Eiffel Tower is one of the most famous buildings in the world. It's not just a symbol of Paris, it's symbolic of France as a whole! Located in the Champ de Mars in Paris, the Eiffel Tower was built between 1887 and 1889, and it is one of the most visited paid attractions in the world. You definitely know what it looks like, and maybe you've even visited it, but there's so much you probably don't know about "La Dame De Fer"! So, read on to learn all about its history, how much it weighs, and what surprising things you'll find at the very top of the tower! We've got more history facts too, if you just can't get enough - learn all about the Statue of Liberty, the HMS Titanic, and the River Thames!

1. It's named after Gustave Eiffel

Gustave Eiffel (1832 - 1923) was a French engineer who specialised in designing and building amazing metal structures and frameworks. He worked on way too many to list here, but they include the Porto Viaduct in Portugal, the Budapest train station in Hungary, the Ruhnu Lighthouse in Estonia, and the Bolivar Bridge in Peru. You might also have heard of another project he worked on - The Statue of Liberty! Eiffel's company built the metal framework inside the statue, which was designed by French sculptor Auguste Bartholdi. The statue was a gift from France to celebrate the centenary of the American Declaration of Independence. So, you could say that the Eiffel Tower and the Statue of Liberty are sisters!

2. But he's not really the brains behind the tower!

The Tower is named after Gustave Eiffel, but it was mainly designed by two other guys, Maurice Koechlin and Émile Nougier. They worked for Eiffel's company, Compagnie des Établissements Eiffel, and had the idea of building a very tall tower with an A-frame. They were concerned that the public might not like the tower's utilitarian metal framework, and so they commissioned an architect named Stephen Sauvestre to make it look prettier. Sauvestre added the Tower's famous decorative arches, the glass pavilion on the first level, and the cupola on top.

3. It was built for a special event

The Eiffel Tower was built for the 1889 World's Fair in Paris (also known as the Paris Exposition Universelle). A World's Fair is a huge exhibition designed to showcase the culture and achievements of participating countries - kind of like the Olympics, but for science, culture and architecture instead of sports! They were hosted by a chosen city (London had an especially famous exhibition in 1851), and the experience would be a grand day out for everyone who went. You could see amazing new inventions, try new foods, and marvel at beautiful purpose-built pavilions! The architects of the 1889 Exposition wanted an impressive structure to be one of the main attractions. It was the centenary of the French Revolution, and the building would represent France's new values of liberty, equality and fraternity.

4. It's made of iron

The architects knew metal had to be used for such a tall tower as wood was too fragile, stone would have collapsed under its own weight, and concrete wasn't very widely used yet. So, the Tower is made of iron - puddle iron, to be precise! Puddle iron is made when pig iron (or crude iron) goes through a refining process, known as puddling. This removes the excess carbon and makes almost pure iron, which Gustave Eiffel considered the very best and strongest material to build with. The iron came from the Pompey forges in the east of France, and then forged in Eiffel's Paris factories. In French the Eiffel Tower is sometimes called "la dame de fer", which means "the iron lady"! Iron corrodes in the open air, so the entire tower is coated in paint, which is redone (mostly by hand!) every seven years.

5. It's HEAVY

A tall building made of iron is definitely going to weigh a lot, and the Eiffel Tower comes in at about 10,100 tons! The iron framework is about 7,300 tons, and the paint also adds 60 tons! The wide bases of the Tower means that this weight is evenly distributed, so even though it's extremely heavy it doesn't sink into the ground.

6. It's also very tall

The Eiffel Tower is a stunning 1083 feet tall - that's about 81 storeys! It was shorter when it was first built, coming in at 1024 feet, but it officially became taller after antennae were later added. When it was built it was the tallest manmade structure in the entire world! It held this honour until 1930, when the Chrysler Building was completed in New York. The current tallest building in the world is the Burj Khalifa in Dubai, which is an eye-popping 2,717 feet tall. But the Eiffel Tower is still the tallest building in Paris, and the second tallest in France!

7. It has three levels

If you want to climb the Eiffel Tower, you can stop and admire the view on three different platforms! The first floor (187 feet tall) is accessible by lifts or by stairs, and it has a restaurant and other facilities. The second floor (377 feet) is also accessible to the public by lift or by stairs, and it has a Michelin-starred restaurant called Le Jules Verne (named after the famous French author) and a macaron bar. The third floor (906 feet) is only accessible to the public by lift, though there is a staircase. It has a champagne bar, and a historical reconstruction of Eiffel's office (more on that later!).

8. Not everyone was a fan!

The Eiffel Tower is super iconic nowadays - but it hasn't always been so beloved! Lots of people objected to the planned tower because they thought it would be impossible to build - and because they thought it was just plain ugly! In 1887 a petition called "Artists against the Eiffel Tower" was sent to the comissioner of the Exposition, signed by famous artists like painter William-Adolphe Bouguereau and writer Guy de Maupassant. They called the Tower "useless and monstrous" and said it would overshadow the beautiful classical architecture of Paris. Eiffel responded by comparing the Tower to the Egyptian pyramids, saying that it would represent the abilities of mankind. Some of the critics changed their minds once the Tower was built, others definitely didn't. Guy de Maupassant apparently liked to eat lunch in the Tower's restaurant, because it was the only place in Paris where he couldn't see the Eiffel Tower!

9. It wasn't supposed to be permanent

The Eiffel Tower was built for the 1889 Exposition, but (like the other buildings constructed for the event) it was only supposed to be temporary! The original plan was to tear it down in 1909, after 20 years. But Gustave Eiffel had a clever plan to save the Tower. He incorporated a radio antenna and a wireless telegraph transmitter into the Tower's design. This made the Tower really useful, and Eiffel was granted another 70 years on its lease. It came in especially useful during the First World War, where the radio transmitter jammed German radio signals, helping to slow the German advance into France, and also allowed the French to pick up on enemy signals from Berlin. By 1980 the lease was up again - but by now the Eiffel Tower was far too symbolic and beloved!

10. There's a secret penthouse!

Well, it's not exactly a secret, but it WAS closed to the public for a long time! Gustave Eiffel incorporated a private apartment into the top floor of the tower for his own personal use. The apartment was small but comfy, and it offered the most spectacular views in all of Paris! Eiffel used to invite special guests to the apartment, including American inventor Thomas Edison. He also used the apartment to conduct his own scientific experiments about the resistance of falling objects (i.e. dropping things), and to take meteorological readings.

11. It's been home to a lot of things

The Eiffel Tower has been home to a number of different things over its lifespan. One of the most interesting was a post office on the first floor, which was open during the Exposition. It was the smallest post office in Paris, and visitors could send letters and postcards with a special Eiffel Tower postmark. At this time it was also home to the French newspaper Le Figaro, who had an office on the first floor where visitors could watch the workers put the paper together. The first floor also had a theatre, which was there until the First World War. On the third floor there were laboratories for scientific experiments, and from 1937 until 1981 there was a large restaurant right at the top, too. It was removed because it was too heavy, and transported to New Orleans, where it still stands today.

12. It was almost destroyed

In 1940 Paris was occupied by Germany during the Second World War. The French cut the lift cables to limit German access, so Nazi soldiers had to climb the tower by foot to hoist their flag from it. In 1944 Allied forces were approaching Paris, and Hitler ordered his generals to destroy the Tower, along with several other important Parisian buildings. The order was not carried out, and the Tower survived the war.

13. It moves!

Tall buildings are susceptible to high winds, and so it's important to make them slightly flexible. The Eiffel Tower sways slightly during high winds, but don't worry - it's supposed to do that! The sun also has an effect on the Tower - in summer the iron expands, and the Tower will also lean away from the sun, which causes it to move during the day. On a hot summer's day, it will move in a circle about 15cm in diameter!

14. Some people can't take photos at night

Every night the Eiffel Tower lights up and dazzles the public with sparkles and golden light, and light shows for special events and commemorations. But these light shows are actually copyrighted! Don't worry, you're not gonna get in trouble for taking pics and posting them on Instagram - but professional and commercial photographers need permission to use the pictures they take!

15. It has 72 famous names engraved on it

The first level of the Tower has the names of 72 famous scientists, engineers and mathematicians engraved into it. Eiffel chose to do this because he was concerned about protests over the Tower, and thought that honouring science would dissuade the criticism. The engravings were painted over in the early 20th century, but restored in the 1980s. There has been some criticism of this - for one thing, it's missing several notable people. There are also no women on the list, even though there were several French women scientists and mathematicians by 1889, including Sophie Germain, whose work on the theory of elasticity helped build the Tower!