Nelson Mandela in London to Celebrate 90th Birthday

Nelson Mandela, the former President of South Africa and anti-apartheid activist, arrived in London Monday to celebrate his upcoming 90th birthday.

Mandela will attend a variety of activities that have been organized for this celebration. Mandela is expected to meet with British Prime Minister Gordon Brown, former U.S. President Bill Clinton and talk show host Oprah Winfrey, among other celebrities and supporters.

In addition to these activities, a concert is scheduled for Hyde Park on Friday that will include performances by Queen, Annie Lennox, Leona Lewis, and the Soweto Gospel Choir.

The concert is titled 46664, after the prison number Mandela wore while incarcerated by South Africa's apartheid authorities. Proceeds from the event will fund the 46664 AIDS charity.

Mandela's birthday is on July 18.

In 1994, Mandela was the first South African president to be elected in fully representative democratic elections.

Before 1990, Mandela spent 27 years in prison for his activism and for being the leader of the anti-apartheid paramilitary forces. He became the leader of the African National Congress's armed wing, Umkhonto we Sizwe (Spear of the Nation), in 1961.

After his release in 1990, which was broadcast live all over the world, Mandela led the party in the multi-party negotiations that led to the country's first multi-racial elections. In 1994 he won the presidential mandate with 62 percent of votes; however, he did not run for a second term and retired in 1999.