John F. Kennedy, left, walks to his inauguration ceremony alongside his wife, Jackie Kennedy. Kennedy was sworn in as the 35th President of the United States on January 20, 1961. Paul Schutzer/The LIFE Picture Collection/Getty Images

Kennedy, seated third from left, on Inauguration Day. Kennedy was both the first Catholic and one of the youngest people elected to the presidency. In 1960, the Massachusetts senator was 43 years old when he won the presidential election against Republican nominee Vice President Richard Nixon, far right. Paul Schutzer/The LIFE Picture Collection/Getty Images

Kennedy greets Robert Frost, right, after a reading by the poet. Frost recited from memory his poem, "The Gift Outright," marking the first time a poet participated in an inaugural program. According to the Academy of American Poets , Frost had written a new piece for the occasion called "Dedication," which he planned to recite as a preface to "The Gift Outright." But it was a cold and sunny day, and because of the bright sunlight reflecting off the snow-covered grounds, he was unable to see and read his newly composed piece. George Silk/The LIFE Picture Collection/Getty Images

Kennedy delivers his inaugural address. In it, he spoke what would become one of his most quoted remarks: "And so, my fellow Americans: Ask not what your country can do for you, ask what you can do for your country." Bettmann Archive/Getty Images

Jackie Kennedy greets her husband in the rotunda of the Capitol moments after he was sworn in as president. The pair married in September 1953, when she was then 24-year-old Jacqueline Bouvier, a writer with the Washington Times-Herald, and he a 36-year-old senator. They had two children who survived: Caroline and John Jr. Henry Burroughs/AP

A view of the inaugural parade. The tradition, according to the Joint Congressional Committee on Inaugural Ceremonies , dates back to George Washington's inauguration in 1789. Early parades mostly consisted of military escorts, but by 1841, when William Henry Harrison was inaugurated, they began to feature floats, citizens groups and bands. Yale Joel/The LIFE Picture Collection/Getty Images

The US 3rd Armored Cavalry Regiment showcases a missile as the parade moves past the presidential viewing stand. Dennis Stock/Magnum Photos

Legendary entertainer Frank Sinatra, center, prepares for the inaugural gala the night before Kennedy's inauguration. Sinatra had campaigned for Kennedy and had worked to organize a star-studded gala for him. Among those who attended were Harry Belafonte, Nat King Cole, Gene Kelly and Bette Davis. Dennis Stock/Magnum Photos

Jackie Kennedy at her husband's inauguration. She became first lady at age 31, and in her role she was deeply committed to promoting the arts and culture. She could speak several languages, including French, Spanish and Italian, and often accompanied her husband on his trips abroad. As a family, the Kennedys are said to have brought a youthful vibrancy, grace and eloquence to the White House. Paul Schutzer/The LIFE Picture Collection/Getty Images