A worshipper wearing a kerchief with the image of the Our Lady of Fatima attends a mass at the Our Lady of Fatima shrine, in Fatima, central Portugal, Wednesday, May 13, 2015. Every year on May 12 and 13 tens of thousands of Catholic believers go on pilgrimage to the Fatima sanctuary to pray and attend masses where the apparitions of the Virgin Mary were witnessed by three shepherd children Lucia, Jacinta and Francisco in 1917. (Photo by Francisco Seco/AP Photo)

A runner in fancy dress participates in the Virgin London Marathon 2013 on April 21, 2013 in London, England. (Photo by Tom Dulat/Getty Images)

In this picture made available Thursday July 11, 2013 a zoo-keeper presents three of twelve ferret babies at Eekholt Zoo in Grossenaspe, Germany, Wednesday July 10, 2013. The ferret babies were born May 25, 2013. (Photo by Markus Scholz/AP Photo/Dpa)

View at one of the sculptures by Swiss artist H.R. Giger during the opening of the Ars Electronica 2013 exhibition “HR Giger. The Art of Biomechanics” in Linz, Austria, 04 September 2013. (Photo by EPA/RUBRA)

Storm chaser Brad Mack from Buena Park California videotapes a rotating supercell storm west of Newcastle, Texas April 9, 2013. Many of the storms in Tornado Alley that were forecast to be severe this week were taken out by a cold front from Canada. Picture taken April 9, 2013. (Photo by Gene Blevins/Reuters)

This combination of April 15, 2013 and April 2, 2014 photos show a police officer clearing Boylston Street following a bomb blast near the finish line of the 2013 Boston Marathon, and pedestrians crossing at the same corner nearly a year later in Boston. (Photo by Charles Krupa/AP Photo)

A visitor looks at a sculpture entitled “Couple Under an Umbrella, 2013” by artist Ron Mueck during the press day for his exhibition at the Fondation Cartier pour l'art contemporain in Paris April 15, 2013. (Photo by Charles Platiau/Reuters)