Question: How long was the eiffel tower the tallest building in the world?
Disambiguated questions and answers: question: How long was the eiffel tower the tallest man-made structure in the world?
How long was the eiffel tower the tallest tower in the world?
answer: 41 years
41
from 1889, when it was built, until 1930
1889–1958
Natural Questions answer: 41 years (from the Wikipedia article "Eiffel Tower")