A visitor kneels down nex to an iCub robot made by the Italian Institute of Technology at the scientists congress IROS 2015 in Hamburg, Germany October 2, 2015. The robot congress is organized by TAMS group (Technical Aspects of Multimodal Systems) of Hamburg's university. (Photo by Fabian Bimmer/Reuters)

The CBRE Urban Photographer of the Year competition – now in its ninth year – encourages professional and amateur photographers to capture cities at work. Here: Dog Walker – 15:00. The competition allows photographers to enter up to 24 images, one representing each hour of the day. (Photo by Johanna Siegmann)

A surfer runs down the beach past hundreds of Barbie dolls comprising the sculpture 'Wave 2' by West Australian artist Annette Thas on Tamarama Beach during the 19th annual Sculptures by the Sea exhibition in Sydney, October 23, 2015. Sydney's coastal walk between Bondi and Tamarama has been transformed into a temporary sculpture park featuring over 100 sculptures from Australian and international artists, billed as the largest free sculpture exhibition in the world. (Photo by Jason Reed/Reuters)

An Acehnese female police officer wear a hijab on duty in the street in Banda Aceh, Indonesia, 27 March 2015. Indonesia National Police officially issued a regulation allowing female police officer to wear the Islamic hijab (heads craft) as a part of their uniform. Indonesia is the biggest Muslim population in the world. (Photo by Hotli Simanjuntak/EPA)

Ukrainian Air Force officers attend a graduation ceremony at the National University of Defence of Ukraine in Kiev, April 24, 2015. (Photo by Gleb Garanich/Reuters)

Winner of the National Park Foundation's photo contest; Honorable Mention: Fan Favorite. Grand Canyon National Park, Arizona. Three friends enjoy sunrise over the Grand Canyon. (Photo by Peter Blanchard)

Private Wallace Tratford arrives home on leave, Drouin, Victoria, ca. 1944. A.I.F. Private Wallace Tratford, son of 1st Constable James Tratford, Drouin's only policeman (responsible for area of 105 square miles; 3,000 people), arrives home on his first leave from New Guinea battlefronts since he was married.

Katie Francis, a member of the Difficult Access Team from Wiss, Janney, Elstner Associates, inspects a gargoyle while rapelling down one of the north tower on the west front of the National Cathedral while looking for damage from August's magnitude 5.8 earthquake and high winds from Hurricane Irene October 17, 2011 in Washington, DC. DAT members used cameras, cell phones and iPad computers to record places on the cathedral's west front where damage was apparent. (Photo by Chip Somodevilla/Getty Images)