Pope Francis greets the crowd from his popemobile in downtown Rio de Janeiro. Pope Francis touched down in Rio de Janeiro on Monday, starting his first foreign trip as pontiff and a weeklong series of events expected to attract more than a million people to a gathering of young faithful in Brazil, home to the world's largest Roman Catholic population. (Photo by Ueslei Marcelino/Reuters)

A man poses standing on a rock looking at the aurora borealis, or northern lights, illuminating the night sky at Embleton Bay in Northumberland, England, on February 27, 2014. The northern lights is a fantastical natural light display with fast moving light effects caused by particles charged by the sun colliding with particles in Earth's upper atmosphere. (Photo by Tom White/PA Wire)

Nine year old girl Barsati reacts while walking on a tightrope in Mumbai on February 11, 2014. Barsati, and her younger brother Rajababu, (4) earn an average of around 2000 rupees (32 dollars) per day from pedestrians and tourists performing various acts on the tightrope near the city's iconic landmark Gateway of India. (Photo by Indranil Mukherjee/AFP Photo)

Nasar, an Arabian horse, stands in the office of doctor Stephanie Arndt at her home on February 19, 2014 in Holt, Germany. Fearing for the horse's safety, Mrs. Arndt brought the horse into her house during the Xaver heavy storm back in December, and the horse now wanders through the house daily, inspecting details and looking for snacks. Mrs. Arndt says she doesn't mind, and though the horse never spends the night, it does occasionally take a nap in the house. (Photo by Patrick Lux/Getty Images)

Tourists and journalists stand next to a newly displayed statue of pharaoh Amenhotep III and his wife Tiye (Down) in Egypt's temple city of Luxor on March 23, 2014. Two colossal statues of pharaoh Amenhotep III were unveiled by archaeologists today in their original sites in the funerary temple of the king, on the west bank of the Nile in Luxor, adding to the existing two famous ancient Memnon colossi. (Photo by Khaled Desouki/AFP Photo)

Painted eggshell displayed at Wayan Sadra's workshop on April 14, 2014 in Sukawati, Gianyar, Bali, Indonesia. 50-year-old Wayan Sadra got the idea to start his eggshell painting business, after his niece who worked in a five star hotel asked for his help to paint on an egg for an Easter egg competition. Now the business he started in 1997 attracts customers for his painted eggs from Germany, France, Italy, and the Netherlands. Sadra usually experiences a surge in sales ahead of Easter. (Photo by Putu Sayoga/Getty Images)

Artist Rachel Stubbs works on the final touches of a sand sculpture she has built as part of this year's “Once Upon a Time” themed annual Weston-super-Mare Sand Sculpture festival on April 16, 2014 in Weston-Super-Mare, England. Due to open on Good Friday, a team of award winning sand sculptors from across the globe have been working to create sand sculptures influenced by fairy tales and fables but that also include some current television and cinema blockbuster hits such as The Hunger Games, Game of Thrones and The Hobbit. (Photo by Matt Cardy/Getty Images)

This undated photograph shows one of the 14 new species of so-called dancing frogs discovered by a team headed by University of Delhi professor Sathyabhama Das Biju in the jungle mountains of southern India. The study listing the new species brings the number of known Indian dancing frogs to 24 and attempts the first near-complete taxonomic sampling of the single-genus family found exclusively in southern India's lush mountain range called the Western Ghats, which stretches 1,600 kilometers (990 miles) from the west state of Maharashtra down to the country's southern tip. (Photo by Satyabhama Das Biju/AP Photo)