Vice President Joe Biden, left, accompanied by his wife wife Jill Biden, signs a condolence book inside the South African Embassy in Washington, Monday, Dec. 9, 2013, as they paid their respects to former South African President Nelson Mandela. During the visit Biden said that the former president was, "the most remarkable man I met in my whole career." President Obama is en route to South Africa to attend a Tuesday memorial service for Mandela. (AP Photo/Jacquelyn Martin)