On 4 Aug, 17:51, Adam Aglionby wrote:
Obviously roofing grade concrete
http://www.youtube.com/watch?v=diZU4bfxrKw

Flour mill. They're always difficult to demolish, as they're so
strongly constructed. Must be one of the few buildings where you could
tip it on its side without it immediately self-dismantling under
gravity.

One does wonder though just WTF the demolition engineer thought he was
doing with such asymmetry though?