A series of explosions in quick sequence shattered Saturday's still morning air in downtown Salt Lake City, and seconds later what once was Utah's tallest bank tower fell in on itself in a billowing cloud of dust and was reduced to a pile of rubble. The implosion of the former Key Bank tower - which once stood next to the Crossroads Plaza mall - has been in the works for months to make way for the City Creek Center project. The deed was done in a matter of seconds at 6:40 a.m. - five minutes early to beat an advancing storm.