Somehow, I don’t remember this great tragedy.  On this date in 1995, the Sampoong Department Store in Seoul, South Korea collapsed killing 502 and injuring 937.  There were signs that an impending collapse was coming as early as April that year.  However, even when it opened back in 1990, there were problems.  The air conditioning was an issue.  The morning of the day of collapse, there were cracks, and all that management did was close shops on the top floor and turn the air conditioning off.

Five hours before the collapse, there was a series of loud bangs and plenty of vibration.  At about five P.M., the fifth floor began sinking, and customers were blocked from that floor.  Even 57 minutes before the collapse, the stores were packed.  No repairs were carried out nor were the shops evacuated.  At 5:50 (seven minutes before the collapse), cracking sounds grew louder, and alarms were sounded.  Evacuations were coming too late.  At 5:57 P.M., the roof gave way, and the air conditioning collapsed through the fifth floor.  Within twenty seconds, the entire building collapsed, thus trapping over 1500 people.  There was 270 million dollars worth of property damage.

Within minutes, rescue crews were working to free trapped people.  There were a precious few who were rescued even after the search for living humans was called off.  There was much public outrage, and there was even a trial where the owner and his son were held responsible for the tragedy.

For more information:

http://en.wikipedia.org/wiki/Sampoong_Department_Store_collapse

https://failures.wikispaces.com/Sampoong+Department+Store

http://www.freebase.com/m/0630cc

http://www.nema.go.kr/eng/m4_samp.jsp