Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

People take photos with the skyline of the central business district in Singapore on September 10, 2015. (Photo by Edgar Su/Reuters)

People are reflected on a soap bubble lying on a road during the evening in New Delhi, India, June 23, 2015. (Photo by Anindito Mukherjee/Reuters)

Policemen take pictures of the Soyuz TMA-17M spacecraft while it is transported from an assembling hangar to its launch pad at the Baikonur cosmodrome, Kazakhstan, July 20, 2015. The Soyuz is scheduled to blast off with Kjell Lindgren of the U.S., Kimiya Yui of Japan and Oleg Kononenko of Russia to the International Space Station on July 23, 2015. (Photo by Shamil Zhumatov/Reuters)

The moon rises behind the skyline and financial district in Toronto, November 25, 2015. (Photo by Mark Blinch/Reuters)

Emilio Gonzalez from Venezuela poses during the Cali Tattoo Festival in Cali, Colombia, September 12, 2015. (Photo by Jaime Saldarriaga/Reuters)

People are reflected in a shop window as they walk along a street in a shopping district in Tokyo, Japan June 25, 2015. (Photo by Thomas Peter/Reuters)

A migrant boy sits on railway tracks at a train station in Tovarnik, Croatia, September 20, 2015. (Photo by Antonio Bronic/Reuters)