A man poses for a picture to show his rings of gold, silver and bronze on his fist in Zamfara, Nigeria April 21, 2016. (Photo by Afolabi Sotunde/Reuters)

Palestinian bedouin shepherds pull their lambs into the water to wash them, in Gaza City, on April 29, 2016. Every year before the beginning of the summer, shepherds wash their herds in the sea. (Photo by Mohammed Abed/AFP Photo)

Cat lounges and makes itself at home at the new Cat Café by Purina ONE on Wednesday, April 23, 2014 in New York. (Photo by Amy Sussman/Invision for Purina ONE/AP Images)

A comedic photo of a cheetah appearing to find something hilarious by Dutton Robert for the Comedy Wildlife Photo Awards 2016, South Africa, April, 2012. (Photo by Dutton Robert/Barcroft Images/Comedy Wildlife Photo Awards)

“A prototype lunar lander was destroyed on August 9, 2012, at Kennedy Space Center during its first free flight”. – James Dean via Florida Today

Photo: Morpheus Ground Level Hot Fire. Photo Date: April 2nd 2012. Location: VTB Flight Complex; Photographer: Joe Bibby

Space Shuttle Discovery is towed from the shuttle landing facility to the orbiter processing facility at Kennedy Space Center on April 20, 2010 in Cape Canaveral, Florida. Discovery's landing attempts at KSC were scrubbed yesterday due to unacceptable weather conditions. Discovery is returning from a successful mission to the International Space Station. (Photo by Matt Stroshane/Getty Images). CAPE CANAVERAL, FL – APRIL 20 2010

Girls pose during a photocall to promote the Big Royal Wedding Sleepover at “Camp Royale” on Clapham Common on March 8, 2011 in London, England. The “Pop Up” campsite will cater for up to 10,500 people between April 28 and May 1 to coincide with the weekend of the Royal Wedding on April 29. (Photo by Dan Kitwood/Getty Images). LONDON, ENGLAND – MARCH 08 2011

In this image provided by the Ministry of Defence, Prince William takes the controls of a Sea King helicopter on April 14, 2011 in Holyhead, Wales. Search and rescue co-pilot Prince William, based at RAF Valley will marry his fiancee Catherine Middleton in Westminster Abbey in London on April 29, 2011. (Photo by MoD Crown Copyright via Getty Images)