Now Playing: Aly Raisman blasts USA Gymnastics CEO over handling of sex abuse scandal

Now Playing: Fast facts about Labor Day

Now Playing: This day in history: Sept. 10

Now Playing: This day in history: Sept. 11

Now Playing: A look at North Korea's 'Mass Games'

Now Playing: Steve Jobs talks iPhone launch in 2007

Now Playing: Freezing the dead with cryonics

Now Playing: Aretha Franklin awarded Medal of Freedom in 2005

Now Playing: Inside the Madonna music and fashion craze of 1985

Now Playing: Aretha Franklin sings at Obama's inauguration

Now Playing: Oct. 12, 1998: Matthew Shepard dies after being attacked

Now Playing: June 20, 1979: ABC News correspondent shot dead in Nicaragua

Now Playing: Alan Alda on fame and family

Now Playing: Columbine High School principal speaks in wake of 1999 shooting

Now Playing: The 1999 crisis in Kosovo

Now Playing: George and Barbara Bush talk personality traits

Now Playing: Trump in 2015: Oprah would be a 'great' running mate

Now Playing: Martin Luther King Jr. discusses attempts on his life in 1965

Now Playing: Martin Luther King Jr. talks 'Issue and Answers' on ABC in 1967

Now Playing: The animal attraction of Koko