Season 4

On September 11, 2001 two aircraft are deliberately flown into two buildings of the World Trade Center and one is flown into the Pentagon. Another crashes in a field in rural Pennsylvania.

On December 7, 1941 Japanese forces attack United States military installations in and around Pearl Harbor, thus bringing the US into World War II.

On October 5, 1999 two trains collide at Ladbroke Grove junction near London's Paddington station after the driver of one fails to stop his train at a red signal.

On July 1, 2002 a cargo airliner and a passenger airliner collide while they are over Überlingen in Germany. The two aircraft crash, killing all on board.

The Cavalese cable car disaster of 1998 (as distinct from a cable car disaster in the same location in 1976), occurred on 3 February 1998 near the Italian town of Cavalese, a ski resort located in the Dolomites, some 40 km north-east of Trento. The disaster, which led to the death of 20 people, occurred when a U.S. military plane cut a cable supporting a gondola of an aerial tramway.

On December 2, 1984 in Bhopal, India, a toxic gas leak at a Union Carbide chemical plant results in the deaths of 3,000 people.