People gather on the Hollywood Walk of Fame in Los Angeles to pay their respects to Olivia Newton-John, who died on Monday, at age 73, after a 30-year battle with cancer. The star of "Grease" and multiple Grammy-winning entertainer, whose career spanned more than five decades, including chart-topping songs such as "Physical," devoted much of her time in later years to charities after first being diagnosed with breast cancer in 1992. IMAGES AND SOUNDBITES