The air Tenerife disaster, KLM Flight 4805 and Pan AM Flight 1736. The two planes had crashed in to one another.
chernobyl?
Ukraine
it was 9/11 in 2001 September 11.3 airlines crash into the 2 twin building
Easily the world's worst Earthquake.
the worlds worst flood was in poland 1997 :)
The Cyclone Mahira in 1899 was the worst natural disaster in Australia.
eastland disaster
Some of the worlds worst air disasters include the two planes that crashed into the world trade center on 9/11/2001 terrorist attack. The pan am plane that crashed in the Canary Islands in 1977 killing 583 is another terrible air disaster.
Asia, specifically the Chernobyl Disaster in the former Soviet Union (Russia), in which a nuclear power plant went critical and melted down, rendering the city uninhabitable and causing radioactive clouds to travel globally.
Hurricane Katrina was the costliest U.S. natural disaster, and one of the deadliest. So it ranks as one of the worst U.S. disasters, but probably not the worst.
The shuttle program began with the flight of the columbia, and its worst disaster was the explosion of the challenger.
It depends. The worst disaster can be anything. Like if someone you love dies or your house burns down. It's an opinion.