On 20 December 1989 more than 20,000 US soldiers descended on Panama.

General Manuel Noriega - the country's leader - sought refuge with the Papal Ambassador.

Witness hears from a young man drafted in to help communicate with the US troops.

It is seven years since one of the Washington snipers, Lee Boyd Malvo, was convicted of murder.

He and John Allen Muhammad had terrorised the US capital for three weeks in autumn 2002, killing at random.

Witness hears from one man who lost his brother during their rampage.

On 16 December 1998 the US and Britain began a four day bombardment of Iraq.

Their justification for Operation Desert Fox was Iraq's failure to comply with United Nations resolutions on disarmament.

Prakash Shah was the UN special representative in Baghdad - he lived through the bombing.

"The destruction of Grozny was apocalyptic... I saw a lot of deaths. I saw people who got wounded by shrapnel from mortar fire and they were dying very slow deaths. But it was very difficult to go and help them because the next target could be you."

In December 1994, Russian forces invaded Chechnya and laid siege to the capital Grozny.

Aslan Doukaev was a university teacher when the first Chechen war began.

He survived months of conflict on the streets before leaving the city for the safety of the mountains.

Hiding in a hole in the ground, bearded and unkempt, the former President of Iraq, Saddam Hussein, was dragged blinking into the light by American special forces.

So how did it feel for Iraqis? Muwaffaq al Rubaie had suffered at his hands and was asked to go and identify the former dictator.

After eight years of military rule, thousands of mainly young, left-wing, Argentinians had gone missing - 'the disappeared'.

Miriam Lewin was one of the few who survived, she talks to Witness.

Smallpox was once one of the most feared diseases in the world - disfiguring and often deadly.

Donald Henderson is the American doctor who led the fight to rid the world of this terrible disease.

His campaign started in the 1960s, and international scientists only agreed that he and his team had succeeded on 9 December, 1979.

He tells Witness how they tackled virus - in the laboratory, and on the ground.

Image: Smallpox cell, Credit: Getty Images

It is exactly 30 years since the former Beatle, John Lennon, was shot dead in New York.

Two days before John Lennon was killed, he spent several hours talking to a young BBC music journalist, Andy Peebles.

For Witness, Andy remembers the man he met - his mood, his conversation, his wit.

Andy Peebles with John and Yoko

When Japanese bombers and fighter planes attacked the US fleet in the Pacific it came as a huge surprise to many. Listen to some archive recordings from the time.

In December 1992, the US sent armed troops into Somalia to help protect aid convoys carrying food to the hungry. They called it Operation Restore Hope - but it was not universally welcomed.