President Barack Obama and Michelle Obama are seen here on their wedding day, Oct. 18, 1992, in Chicago, Ill. Obama for America/AP/FILE
Former President George W. Bush stands with his daughter, Jenna, at her wedding to Henry Hager at Prairie Chapel Ranch in Crawford, Texas, on May 10, 2008. Shealah Craighead/UPI/Newscom/FILE
Secretary of State Hillary Clinton is seen here with former President Bill Clinton on their wedding day in Fayetteville, Ark., on Oct. 11, 1975. Clinton Press Office/Newscom/FILE
President John F. Kennedy's daughter Caroline is seen with her Uncle Teddy Kennedy on her wedding day in July 1986 in Centerville, Mass. Newscom/FILE
John F. Kennedy and Jacqueline Lee Bouvier are seen on their wedding day on Sept. 12, 1953 in Newport, RI. Newscom/FILE
George W. Bush and Laura Bush (c.) are seen on their wedding day with their familes in Midland, Texas, on Oct. 1, 1977. Newscom/FILE
Amy Carter, daughter of former President Jimmy Carter, poses with her husband Jim Wentzel after they were married in Plains, Ga., in September 1996. Charles Plant/Carter Family/AP/FILE
Newlyweds Ronald Reagan and Nancy Reagan cut their wedding cake on March 4, 1952. Newscom/FILE
President Richard M. Nixon, First Lady Pat Nixon, and newlyweds Tricia Nixon Cox and Edward Cox stand in the receiving line at the White House on June 12, 1971, following their wedding ceremony in the Rose Garden. Newscom/FILE
Former President Harry Truman is seen with his wife Bess on their wedding day in Independence, Mo., on June 28, 1919. Harry S. Truman Library and Museum/UPI/Newscom/FILE
Former President Franklin D. Roosevelt's wife Eleanor is seen here on her wedding day. Newscom/FILE
President Theodore Roosevelt is seen here with his daughter, Alice, and her husband Nicholas Longworth on their wedding day at the White House. Newscom/FILE
Marc Mezvinsky, left, with his new mother-in-law Hillary Rodham Clinton, his bride Chelsea and father-in-law former President Bill Clinton after the couples wedding July 31, in Rhinebeck, N.Y. Barbara Kinney/Genevieve de Manio Photography/AP
An outburst of violence in recent days between the Dinka and the Nuer in Sudan could portend civil war in the country, officials warned Wednesday. President Salva Kiir accuses rival Riek Macharf of sparking the violence, but says he is willing to begin a dialogue.
South Sudan's army said it had lost control of the flashpoint town of Bor on Wednesday, its first acknowledged reversal in three days of clashes between rival groups of soldiers that have triggered warnings of a slide into civil war.