A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

An airplane crosses a nearly full-moon on its way to Los Angeles International Airport near Whittier, Calif., Thursday, December 24, 2015. Not since 1977 has a full moon dawned in the skies on Christmas. (Photo by Nick Ut/AP Photo)

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)

Peruvian shamans holding a poster of Russia's President Vladimir Putin perform a ritual of predictions for the new year at Morro Solar hill in Chorrillos, Lima, Peru, December 29, 2015. The ritual is an end-of-the-year tradition and the shamans called for world peace and wished good luck for the upcoming elections in Peru and the U.S. (Photo by Mariana Bazo/Reuters)

Ford is celebrating the 50th anniversary of the Mustang with a limited-edition model and a display atop the Empire State Building. The car had to be broken into five pieces for the ride up the building’s elevators and reassembled late at night, when the deck is closed to visitors. Photo: The 2015 Ford Mustang convertible, assembled overnight, sits on the observation deck of the Empire State Building. (Photo by Hiroko Masuike/The New York Times)

Pilgrims wearing traditional dresses take part during the Queen of Angeles pilgrimage in Alajar, southern Spain, September 8, 2015. Every year, devotees converge at the Arias Montano crag to pay homage to the Queen of Angeles during an annual pilgrimage which combines religious fervour and festive colour. (Photo by Marcelo del Pozo/Reuters)

Huellas, a paraplegic dog in a wheelchair, walks at Pescadores beach in Chorrillos, Lima, September 7, 2015. Sara Moran has an animal shelter called Milagros Perrunos where she cares for stray dogs and shelters dogs injured from traffic accidents or domestic abuses. With donations and raffle, Moran purchases wheelchairs, food and medical treatment for the dogs at her shelter. (Photo by Mariana Bazo/Reuters)

A car enthusiast races at the Goodwood Revival historic motor racing festival in Goodwood, near Chichester in south England, Britain, September 11, 2015. The three-day event held each September at Goodwood Circuit since 1998 attracts thousands dressed in period costume who watch motor racing in vehicles from the mid-twentieth century heyday of the venue. (Photo by Toby Melville/Reuters)