It took just over 26 months to erect the Eiffel Tower, which was a breakneck pace given that it weighs 10,100 tons, stands 1,024 feet tall and is 410 feet wide. 

The landmark on the Champs de Mars in Paris, constructed for the 1889 World’s Fair, would become one of the planet’s iconic structures, but there was no guarantee at the time that the tower would be permanent.

Influential artists called it “monstrous and useless,” and its creator only received a 20-year land-use permit for it.

Engineer-entrepreneur Gustave Eiffel found an ingenious way to justify the tower’s long-term survival: He made sure that the tower’s top was used for scientific experimentation. And the world’s tallest structure at that time also became an important radio transmission point.

Here’s how the tower came into being and overcame the risk of being torn down:

The idea for the vertical spectacle dates to June 1884, when engineers Emile Nouguier and Maurice Koechlin, both employed by Eiffel, decided to construct an imposing tower with intricate lattice work. By September, they registered a patent to bring their vision to life.

The project beat 100 others in the 1886 competition that asked participants to conceptualize an iron tower for the 1889 World's Fair.

“Basically, it was just this big celebration of France's economic and geopolitical importance, and they wanted to have a centerpiece exhibition, and that was the Eiffel Tower,” says Anne O'Neil-Henry, associate professor of French and Francophone Studies at Georgetown University.

The landmark was supposed to be a temporary exhibit tied to the exposition. After its permit ran out, the city of Paris was scheduled to take control of the tower on January 1, 1910, and decide what to do with it.

Construction started on January 26, 1887, and lasted until March 31, 1889. But significant opposition emerged early on from notable detractors.

On February 14, 1887, artists, writers and intellectuals including Guy de Maupassant, Alexandre Dumas, Sully Prudhomme and Charles Garnier published a letter of protest against the project in the Le Temps newspaper. 

Their letter states: “We come, as writers, painters, sculptors, architects, and passionate lovers of the beauty that Paris has until now preserved intact, to protest with all our strength, with all our indignation, in the name of disregarded French taste, in the name of threatened French art and history, against the erection, in the very heart of our capital, of the useless and monstrous Eiffel Tower, which public malice, often marked by common sense and a sense of justice, has already dubbed the Tower of Babel.”

They also called the tower project a “truly tragic street lamp” and a “carcass waiting to be fleshed out.” 

“Charles Garnier, who is the architect of the Paris Opera House, said, ‘It's this horrible thing. It's not architecture. It's just this frame of a building,’” says Lisa D. Schrenk, professor of architectural history in the University of Arizona’s School of Architecture. 

Unlike the building process for Notre Dame, constructed in the 12th century, the fewest materials possible were used to create the Eiffel Tower, Schrenk says.

The tower’s construction sparked debate about whether the engineering marvel would have artistic features or only engineering attributes, says S. Hollis Clayson, professor emerita of art history at Northwestern University.

“The irony of the thing is that when it was built, it was covered with very flowery, some people said, Gothic ornaments, which have since been cut off and thrown away,” she says.

Artists were calling the tower ugly before a third of it was constructed, Clayson says.

“So they were reacting to the broad base of the tower, and that it was 100 percent iron,” she says.

Eiffel defended his project in Le Temps, arguing that it would “have its own beauty.” And he reminded artists that just “because we are engineers, does one assume that beauty does not concern us in our constructions, and that while we strive to build solid and durable structures, we do not also endeavor to make them elegant?”

The 2 million people who flocked to the tower during the 1889 World's Fair proved Eiffel’s declaration that “there is, in the colossal, a unique attraction and charm.” 

Many had to climb stairs to the top because the elevators didn’t work at first. They were rewarded with views of Paris from a new vantage point.  

“You could get a whole perspective of the city in a way that you hadn't been able to before, just because of how tall it was compared to any other building,” O'Neil-Henry says.

Though the Eiffel Tower was wildly popular after it opened, it didn’t generate as much enthusiasm during the 1900 World’s Fair in Paris.

And city officials could not be counted on to preserve the tower. In 1906, they ordered the razing of the Gallery of Machines, another 1889 exposition attraction, because they could not justify keeping open what was once the world’s largest building.

“Once the tower had been up for 20 years, there was a small discussion again, about whether or not it should stand, but there was no objection to keeping it standing,” Clayson says.

But Eiffel needed a guarantee, using science to ensure that the tower would not be demolished. Eiffel behaved “as kind of the engineer, as opposed to really an architect, in how he thought the place at the top should be for scientific experiments,” says Schrenk, who is also the co-founder of the Institute for the Study of International Expositions. “So at the very top, you've got the place where they're looking at atmospheric calculations and other scientific explorations.”

The top of the tower was also used to transmit radio signals via wireless telegraphy, which was an emerging technology at the time. 

Eugène Ducretet, who manufactured scientific instruments, demonstrated this on November 5, 1898, by making radio contact between the Eiffel Tower and the nearby Panthéon mausoleum. In 1899, the tower housed a radio transmitting station that could reach audiences in London.

And with funding from Gustave Eiffel, an antenna was installed at the tower’s peak for 1908 experiments that transmitted radio signals up to 3,700 miles.

The tower’s scientific capabilities led to Eiffel receiving a 70-year extension on his permit. The ability to send and receive radio broadcasts from the tower helped France defend itself from German attacks during World War I. By the end of 1921, Radio Eiffel Tower had started an ongoing broadcast.

The Eiffel Tower’s scientific uses were fitting, because the World’s Fair administrators viewed them as symbols of cutting-edge technology, O'Neil-Henry says.

These days, no one talks about getting rid of the tower.

“It's the symbol of modern Paris,” O'Neil-Henry says. “It still embodies that idea of progress, technological achievement, and national pride.”