Detailed Instructions: In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
Q: Article: Close your eyes and picture the city of Paris.Now imagine the city without its most famous landmark:the Eiffel Tower. The unthinkable almost happened. When French engineer Gustave Eiffel built this tower for the Paris World's Fair of 1889,it was controversial.The iron structure contrasted sharply with the historic stone buildings of Paris.Eiffel's four-legged iron archway was supposed to last only 20 years.That's when Eiffel's permit to operate the building would expire and the city could choose to tear it down. Yet from the beginning.Eiffel had a strategy to save his building.If the Tower was linked to important research,he reasoned,no one would dare to take it down.So he would make it a grand laboratory for science. Scientific research began just one day after the Tower opened to the public on May 6,1889.Eiffel installed a weather station on the Tower's third(and highest)floor.He connected instruments by wire to the French weather bureau in Paris.With these,he measured wind speed and air pressure. In 1903,still worried that his building might be torn down,Eiffel got a clever idea.He asked the French military to conduct its own research on radio communications at the Tower.He even paid the army's costs. French army captain Gustave Ferrie worked from a little wooden house at the base of the Tower's southern pillar.From there,he made radio contact with forts around Paris.Convinced of the importance of radio communications,the army set up a permanent radio station at the Tower.In 1910,the city of Paris renewed the structure's permit for another 70 years. This year marks the iconic structure's 125th birthday.Over the years,research conducted there has brought dramatic and unexpected payoffs.During World War I,for instance,the French army used the Tower as a giant ear to receive radio messages.It even led to the arrest of one of the war's most famous spies.
Answer: The Eiffel Tower was almost torn down.
A:
What does the author mean by"The unthinkable almost happened"?