Aiden Haas, left, and Lilli Alcala pose after being crowned Mud King and Mud Queen at the 29th annual Mud Day, Tuesday, July 12, 2016 in Westland, Mich. The event, open to children 12 and younger, was at the Hines Park-Nankin Mills Area west of Detroit. Children 12 and younger were able to slosh around in the pit while participating in mud limbo, wheelbarrow races and other free activities. (Photo by Carlos Osorio/AP Photo)

Machu Picchu, Peru. A llama’s-eye view of the legendary Inca settlement at Machu Picchu, isolated high in the Peruvian Andes. (Photo by Jim Turner/National Geographic)

A woman takes pictures with her mobile phone at a building, which is made by half of a replica of the Qinian Hall of the Temple of the Heaven (R) and half of a western building, at a studio for productions of films and television shows on the outskirts of Shijiazhuang, Hebei province, China, December 3, 2015. (Photo by Reuters/Stringer)

A spectator cools herself at a water spraying fan at the Australian Open tennis championships in Melbourne, Australia, Tuesday, January 17, 2017. (Photo by Kin Cheung/AP Photo)

The Zhangjiajie National Forest Park is a unique national forest park located in Zhangjiajie City in northern Hunan Province in the People's Republic of China. It is one of several national parks within the Wulingyuan Scenic Area.

Britain's Red Arrows airplane display team perform during D-Day commemorations in Portsmouth in southern England on June 5, 2014. Several hundred surviving veterans of the 1944 D-Day landings are commemorating the 70th anniversary of the mission on both sides of the English channel. (Photo by Carl Court/AFP Photo)

The name “Aiguille du Midi” translates literally as “Needle of the Noon” or “Needle of the South”. It gets its name from its tapered form and from its position when viewed from Chamonix: it approximately indicates noon when the sun passes over its summit.

HRP-4C, a five-foot humanoid robot developed at Japan's National Institute of Advanced Industrial Science and Technology, sings and dances with performers at the Digital Contents Expo in Tokyo on October 17, 2010. The robot runs entertainment software called Choreonoid, a name formed from the words “choreograph” and “humanoid”. (Yoshikazu Tsuno/AFP)