A 174ft tower collapsed in the wrong direction as it was demolished – accidentally crushing a library and cultural centre.
Footage of the explosion, in Denmark, shows books and papers from the other buildings being sent flying.
Nobody was injured but thousands of onlookers watched in horror as the silo crumpled onto the adjoining buildings.
One witness said many people shouted “No, no.”
The tower, which had stood at Vordingborg harbour for 36 years, was being demolished to make way for new homes, businesses and a hotel.
Engineers used 10kg of explosives to bring it down, and after six months of preparations, calculated it would fall in exactly the opposite direction.
“I simply do not know how it may have gone so bad,” blasting manager Kenneth Wegge told Danish news network TV East. “I will put my head on the block.”
Vice chairman of the Danish Explosives Association, Johan Finsteen Gjodvad, said: “When you look at what has been done in preparation, it should fall the other way. It's really unfortunate that it went wrong that way.”
An investigation has been launched as a mass clear-up begins.
A corner of the library building was said to have been wrecked.
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