ROME (CNN) -- Amid pomp and ceremony, Benedict XVI left Vatican City Thursday for the last time as pope, ahead of his historic resignation as leader of the world's 1.2 billion Catholics.

Diplomats emerged Wednesday from an unusually secretive round of talks on Iran's controversial nuclear program with a joint announcement to hold a follow-up meeting within weeks.

Pope Benedict XVI spoke of moments of struggle as well as joy Wednesday during his final public address from a stage set up in St. Peter's Square.

ROME (CNN) -- With only two full days left of Pope Benedict XVI's papacy, more details emerged Tuesday of what the future holds both for the retiring pontiff and the cardinals who will choose his successor.

ROME (CNN) -- Scotland's Roman Catholic archbishop, Cardinal Keith O'Brien, has resigned amid allegations that he abused four men studying to be priests in the 1980s.

At the same time as Pope Benedict XVI leaves office on February 28, his Twitter presence as @Pontifex will also come to an end, according to Vatican Radio.

Pope Benedict XVI is considering changing the Vatican constitution to allow a vote for his successor to begin before March 15, Vatican spokesman the Rev. Federico Lombardi said Wednesday.

The Obama Administration now believes the attack and hostage-taking at a natural gas plant in Algeria last week is the work of al Qaeda operatives based out of northern Mali

LONDON (CNN) -- Britain's Catherine, Duchess of Cambridge, is spending a second day in a central London hospital Tuesday after being admitted with acute morning sickness.

Savita, a 31-year-old dentist, had died of blood poisoning after being denied an abortion for a miscarrying fetus under Ireland's strict laws, her husband says.