Witnesses around the world claim to have spotted mysterious sea creatures, but are these survivors from the age of the dinosaurs or just mistaken sightings?

Thousands of crop circles have been reported. Most are dismissed as hoaxes, but could some be from another world? 

Missing over New York: Seventy-three people were killed when a low-on-fuel flight was caught in a holding pattern over the Big Apple. Who or what was to blame for the tragedy? (S2, ep 6)

Lost!: The pilots were experienced and the navigation system was sophisticated, so why did delayed American Airlines Flight 965 fly into a mountain? Experts investigate. (S2, ep 5)

Deadly Crossroads: Pilots of a Russian plane carrying school children are forced to make a life or death decision when they get caught in the path of a cargo plane. (S2, ep 4)

Killing Machine: In 1994, an Air France flight carrying 180 passengers was hijacked by terrorists. Their aim was to explode it over Paris. Could French special forces stop them? (S2, ep 3)

Wounded Bird: Flight ASA 52 had to fly with one wing during a trip to Mississippi. With no option other than to crash land, it was touch and go whether anyone would survive. (S2, ep 2)

Blow Out: Those aboard British Airways Flight 111 knew something was terribly wrong when there was a bang moments after take-off. Could the inexperienced co-pilot land the plane? (S2, ep 1)

System Breakdown: Check out what it takes to be an air traffic controller. Plus, this new system bids to make mid-air collisions a tragedy of the past. (S2, ep 1)

American Nazis: Past and current Nazi members offer an insight into the US's secret Nazi past and the covert meetings and manifesto of its present-day Neo Nazi groups. (S1, ep 3)