Family members, presidents and celebrities gathered in Washington, D.C. on Wednesday afternoon at a memorial service for Ethel Kennedy, the matriarch of the famous political family who died last week. Ethel Kennedy died last Thursday at the age of 96, following a stroke the week before. She was a social activist and the wife of the late Sen. Robert F. Kennedy.President Joe Biden, former presidents Barack Obama and Bill Clinton, former House Speaker Nancy Pelosi, Martin Luther King III and several others read eulogies during the service at the Cathedral of St. Matthew the Apostle. Stevie Wonder, Sting and Kenny Chesney were among the celebrities who performed at the service.Former Massachusetts Rep. Joe Kennedy III called participants to the podium throughout the service and used his eulogy to share life lessons learned from his grandmother."This life is not promised. Chin up. Mind your manners. Don't waste one precious second not enjoying your life," he said. He also thanked attendees for the outpouring of love and support."As my grandmother would say, 'Aren't we lucky,'" he said. Video below: President Biden spoke at Ethel Kennedy's memorial. Here is some of what he saidObama, who presented Ethel Kennedy with the Presidential Medal of Freedom in 2014, remembered her as "someone who reminds us by her example that life goes on, no matter how deep the grief. That there is joy and purpose to be found, no matter what hand we've been dealt." "Mum brought Joe, Bobby and me to the Senate hearings where daddy was investigating the mob," shared Kathleen Kennedy Townsend, Ethel Kennedy's daughter.A funeral Mass for the Kennedy family and invited guests was held in Centerville on Monday.Ethel Kennedy is survived by nine of her 11 children, 34 grandchildren and 24 great-grandchildren.Ethel Kennedy met Robert Kennedy when she was just 17, and a close friend and roommate of his sister, Jean. The couple married in 1950.Video below: Kennedy family, dignitaries gather on Cape Cod for funeralHer life changed forever with an assassin's bullet in June 1968. She vowed then she would never marry again, and she never did. RFK was buried with his brother, President John F. Kennedy, at Arlington National Cemetery. Ethel Kennedy visited the Eternal Flame in 2013.