What does rock megastar Rod Stewart remember most about playing to 4 million people on Copacabana beach on New Year's Eve 1994? Well... it's not nice.

Photo: Rod Stewart at the BBC.

In December 1999 a young Dutch man, Bart Spring in't Veld, won the first ever Big Brother reality TV show. It was to be the start of a global television phenomenon.

But for 22-year-old Bart the victory proved to be a mixed blessing.

Photo: Big Brother winner Bart Spring in't Veld, Credit: Endemol

In 2004, some of the most high-profile people in Portugual went on trial on charges of sexuallly abusing boys from a children's home called Casa Pia. Six defendants were eventually found guilty, including a famous televison presenter. Simon Watts talks to Pedro Namora, a lawyer who campaigned for the Casa Pia victims.

Photo: Getty Images.

Fought during the winter months of 1944, it was the last major German attack on the Western Allies in World War II. Witness speaks to Keith Davis, an American survivor of the Battle of the Bulge.

Photo: American tanks in Belgium in January 1945. Credit: Hulton Archive/Getty Images.

In 1964 a 'pirate' radio station began broadcasting from a ship off the coast of England, in defiance of British law. Keith Skues was one of the first DJs on Radio Caroline. He tells Witness about the difficulties, and the fun, they had on board.

Photo: Radio Caroline's ship Mi Amigo at anchor off East Anglia, Credit: Evening Standard/Getty Images

On Christmas Eve 1914 the guns fell quiet over the trenches of World War One. Soldiers from British and German regiments exchanged gifts and sang carols. Hear first hand accounts from the BBC archives.

Photo: German and British troops in Belgium in December 1914. Credit: AP/Imperial War Museum

Julia Butterfly Hill lived in an ancient redwood tree in northern California for 738 days to protect it. Her bed was a tiny platform. She speaks to Witness about the challenges and the beauty she experienced during her remarkable solo protest.

(Photo: Julia Butterfly Hill in the ancient redwood tree she called Luna. Credit: AP)

In 2006 the Nepalese government and Maoists signed a peace accord ending 10 years of civil war. Witness has been speaking to the UN envoy to Nepal at the time and to one of the Maoists' lead negotiators.

(Photo: Nepalese Prime Minister Girija Prasad Koiral (L) and Maoist Chairman Prachanda shake hands after they exchanged documents following the signing of a landmark peace agreement, in Kathmandu 21 November 2006. Credit: Devendra M Singh/Getty Images)

In December 1944, American bandleader Glenn Miller went missing over the English Channel. Witness speaks to trombonist Nat Peck, who played in Miller's band.

Photo: Nat Peck (left) with other members of the Glenn Miller Army Air Force Band

It was in January 1961 that the USA first broke off diplomatic relations with Cuba. Wayne Smith was one of the last diplomats to leave the US embassy in Havana.

(Photo: An advert on the Miami waterfront after Fidel Castro came to power. Credit: Graf/Getty Images)