A mosque is pictured under a cloudy sky in Cairo, Egypt, Saturday, April 11, 2015 (Photo: AP)
An Egyptian girl sits under a bridge at the edge of the Nile river under a cloudy sky in Cairo, Egypt, Saturday, April 11, 2015 (Photo: AP)
Christian pilgrims hold candles as they gather at the church of the Holy Sepulcher, traditionally believed to be the burial site of Jesus Christ, during the ceremony of the Holy Fire in Jerusalem's Old City, Saturday, April 11, 2015 (Photo: AP)
A worshipper holds a candle as she takes part in the Christian Orthodox Holy Fire ceremony at the Church of the Holy Sepulchre in Jerusalem's Old City April 11, 2015 (Photo: Reuters)
Pope Francis, top left, and prelates sit inside St. Peter's Basilica at the Vatican, Saturday, April 11, 2015 (Photo: AP)
Militants loyal to Yemen's President Abd-Rabbu Mansour Hadi stand by a tank they used in fighting against Houthi fighters in the southern port city of Aden April 11, 2015 (Photo: Reuters)
A group of Iranian protesters chant slogans in front of the Saudi Embassy, while police officers deploy to protect the embassy, in Tehran, Iran, Saturday, April 11, 2015 (Photo: AP)
A biker is silhouetted as he performs a backflip jump during a bike festival in front of city hall in Vienna, April 11, 2015 (Photo: Reuters)
Clouds rise over the wooden cross on a hill rock at Ayios Epiphanios Christian Orthodox church in southeast coastal resort of Ayia Napa, Cyprus, Saturday, April 11, 2015 (Photo: AP)
Men pass cherry blossoms at a park on a rainy morning in Yokohama, near Tokyo Saturday, April 11, 2015 (Photo: AP)
The crew from the women's Oxford universities rowing team approaches Hammersmith Bridge during the Boat Race on the River Thames in London, April 11, 2015 (Photo: Reuters)
The Washington Monument towers over a cherry tree in full bloom, Saturday, April 11, 2015, in Washington (Photo: AP)