The Bee Gees -- Robin, Barry and Maurice Gibb -- in 1970, before their biggest hits, including "Stayin' Alive." Robin Gibb died May 20, 2012 after a long battle with cancer and intestinal surgery. His twin brother, Maurice, died in 2003

Barry Gibb, top, Robin Gibb, middle, and Maurice Gibb pose in 1971.

Barry Gibb, Maurice Gibb, Peter Frampton and Robin Gibb, left to right, on the set of the film "Sgt. Pepper's Lonely Hearts Club Band," in 1978.

The Bee Gees -- left to right, Maurice, Robin and Barry Gibb -- perform at the Oakland Coliseum on July 11, 1979, in Oakland, Calif. The group had exceptional success in the late 1960's and the 1970's, becoming a disco sensation with blockbuster hits "Stayin' Alive" and "Night Fever."

The Bee Gees pose with Barry Manilow at the American Music Awards, Jan. 18, 1979. From left to right, Barry Gibb, Maurice Gibb, Robin Gibb and Manilow. Manilow won the award for Favorite Pop/Rock Male Artist, and the Bee Gees won Favorite Pop/Rock Band, Duo, or Group.

Maurice Gibb, Robin Gibb and Barry Gibb, left to right, of the Bee Gees at the 1997 American Music Awards.

The Bee Gees pose with Michael Jackson, Diana Ross and members of the Jackson 5.

Maurice Gibb, Barry Gibb and Robin Gibb at the height of their fame.

The Bee Gees -- Maurice, Robin and Barry Gibb -- perform. The Brother's Gibb, as they were sometimes called, began to sing in harmonization and write songs together as young boys in England.

The two surviving members of the Bee Gees, Robin Gibb, left, and Barry Gibb, right, hold their CBEs or Order of the British Empire awards, along with Adam Gibb, who received the honor on behalf of his father, Maurice Gibb, on May 27, 2004 at Buckingham Palace in London. All three brothers were awarded CBEs, although Maurice Gibb had died in 2003 before he could receive the honor.

Barry Gibb, Robin Gibb and Maurice Gibb announced the release of the Bee Gees 22nd album,"This is Where I Came In," at a media conference April 23, 2001 in New York City. It was the final album released before Maurice Gibb died of cardiac arrest just ahead of undergoing a second abdominal surgery at Mount Sinai Medical Center on Jan. 11, 2003 in Miami Beach, Florida.

Maurice Gibb, Robin Gibb and Barry Gibb of the Bee Gees perform at the BG2K Millennium Concert at the National Car Rental Center On Dec. 31, 1999 in Sunrise, Florida.

Musicians Maurice Gibb, Robin Gibb and Barry Gibb of the Bee Gees perform onstage at the Hammerstein Ballroom on April 27, 2001 in New York City.

Musicians Barry Gibb and Robin Gibb of the Bee Gees attend the 25th Annual Rock And Roll Hall of Fame Induction Ceremony at the Waldorf Astoria on March 15, 2010 in New York City.

During happier days, Maurice Gibb, Robin Gibb and Barry Gibb, circa 1998.

Bee Gees Robin Gibb and Barry Gibb during The Bee Gees Receive Honorary Doctorates from the University of Manchester, May 12, 2004, Manchester England.

The remaining Bee Gees, Robin and Barry Gibb, perform on stage during The Prince's Trust 30th Live concert held at the Tower of London on May 20, 2006 in London, England.