19 things you never knew about the Eiffel Tower

The structure may be named after Gustave Eiffel, but it was actually his senior engineers, Maurice Koechlin and Emile Nouguier, who designed the building. Eiffel wasn't overly interested in the project, but sent the engineers to the head of his company’s architectural department, Stephen Sauvestre. With Sauvestre's edits, Eiffel got behind the final plans and bought the rights to the patent.

The pieces of iron are connected by 2.5 million rivets. They were put in place by between 150 and 300 workers who were employed to build the structure.

Digging work on the site of the Eiffel Tower began on January 28, 1887. Over a year later, on April 11, 1888, the tower's first floor was completed, followed by the second floor on August 14, 1888. The final stage was completed on March 31, 1889 — just two years, two months, and five days after construction began.

Or as Eiffel himself said, "not only the art of the modern engineer, but also the century of industry and science in which we are living." At the time that the tower was being built, another technology was also in its infancy — photography. As the tower was assembled, many photographers captured series of photographs to show the tower’s construction.

The Eiffel Tower measures 1,063 feet with its antenna, and 984 feet without it. It wasn't until 1930, when New York City’s Chrysler Building rose to 1,046 feet, that the tower lost its title.

Because it’s made with puddled (wrought) iron, the tower’s metal expands when exposed to the summer sun, causing the structure to rise by as much as 6.75 inches.

On May 6, 1889, fairgoers were allowed to enter the tower, but the 30,000 visitors had to climb 1,710 steps to reach the top. The lifts finally entered service on May 26.

Newspapers received angry letters that said the tower didn’t fit into the feel of the city and there was a team of artists that rejected the plan from the get-go. One apocryphal story says that novelist Guy de Maupassant said he hated the tower, but ate lunch at its restaurant every day. When he was asked why, Maupassant replied that it was the only place in Paris where he couldn’t see it.

But the French military and government began using it for radio communication and later telecommunication. When the permit expired in 1909, the City of Paris decided to keep it.

The tower attracts almost 7 million visitors every year, 75% of them from other countries. 

Unsurprisingly, 15.8% of visitors — the majority, when divided by country — are from France, according to visitor statistics. Outside of the country, Americans visit the most, making up 11.9% of the tower's visitors, followed by British tourists (7.5%).

It transmitted radio signals during WWI and during WWII the elevator wires were cut so that the Nazis could not use the tower (after Allied troops entered the city, the elevators were fixed). It has even survived a fire on its top floor.

The tower continues to be affected by world conflicts. Following the November 2015 terror attacks in Paris, the fences surrounding the structure will be replaced with a bulletproof glass wall as a safety measure.

To counteract atmospheric perspective, the tower is painted darker at the top and becomes gradually lighter toward the bottom. 

Painters apply new layers of lead-free paint to the tower to prevent rust. The process takes 18 months in total.

When the monument was first built for the world fair, it was illuminated by 10,000 gas lamps. It wasn't until 1985 that the tower's golden lighting was introduced, with 336 projectors using sodium bulbs to cast the yellow-orange hue. In 2004, the projectors were replaced with more environmentally friendly ones.

Introduced on the countdown to the 21st century on New Year's Eve in 1999, the beacon and hourly light show have come to define the Eiffel Tower by night. The beacon is powered by automatic computer programs, sending two beams of light across a distance of 49.7 miles.

Every night, 20,000 LED lights adorning the tower — 5,000 on each side — sparkle in a five-minute light show that happens every hour from when it gets dark until 1 a.m.

The tower briefly served as ad space for the car manufacturer Citroën, with 250,000 colorful bulbs and 370 miles of wiring used to write the company's name on the Paris skyline in 1925.

The Eiffel Tower has housed a newspaper office, a post office, scientific laboratories, a theater, and the first level becomes an ice rink every winter.

Eiffel installed a tiny apartment near the top of the tower, where he entertained guests like Thomas Edison and kept a grand piano. Though he was reportedly offered attractive sums of money to sell the space, he never did. Today, visitors can see mannequin versions of Eiffel and Edison in the apartment through small windows.

For more information about the Eiffel Tower, visit its official website.