Warsaw Radio Mast
The Warsaw Radio Mast was the world's tallest structure from 1974 until its collapse on 8 August 1991. It was the second tallest structure ever built, being surpassed as tallest by the Burj Khalifa, completed in 2010.
Till today it is the second tallest human-made structure surpassed by Burj Khalifa in 2010.
It took about 4 years to erect and collapsed 17 years from the time it was completed