The antennas of the European Southern Observatory's Atacama Large Millimeter/Submillimeter Array, also known as ALMA, are set against the splendor of the Milky Way in this picture by Babak Tafreshi. Construction of the full ALMA array is due to be completed in Chile's Atacama Desert in 2013, but the facility is already making scientific observations with a partial array of antennas. (Photo by ESO/B. Tafreshi/TWAN)

A reveller takes part in an annual block party known as “Ceu na Terra” (Heaven on Earth), one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, January 30, 2016. (Photo by Pilar Olivares/Reuters)

A mahout rides an elephant at Tad Sae Waterfall outside Luang Prabang, Laos July 31, 2016. Protected by the United Nations cultural heritage agency UNESCO, Luang Prabang is one of the most alluring places in the region – a city that evokes old-world romance that has gained a reputation as a travellers' Shangri La. (Photo by Jorge Silva/Reuters)

Tong Jieping, 44-year-old mentally disabled patient, is chained by his foot inside his room, in Qunxing village of Wangjiang county, Anhui province, China, July 14, 2015. Tong was diagnosed mentally ill when he was in his 20s. His parents, both in their 70s, could not afford the medical treatments so they had to lock him up in chains to prevent him from running away, according to Tong's family. (Photo by Reuters/Stringer)

Street entertainer and fortune teller “Juana La Cubana” smiles holding a cigar in her mouth as she waits for tourists in Havana, Cuba, Sunday, May 24, 2015. Juana is 72 years old and has worked in the Cathedral square in Old Havana for 28 years. (Photo by Desmond Boylan/AP Photo)

Jorge, an immigrant from Mexico, dressed as the Sesame Street character Elmo rests in Times Square, New York July 29, 2014. Elmo and Cookie Monster have long delighted young viewers on TV's “Sesame Street”, but the recent antics of New York street performers dressed as the beloved characters have drawn the ire of city officials and now the show's producers. Sesame Workshop, which owns the rights to Big Bird, Ernie and the assorted puppet monsters on the 45-year-old program, said on July 29, 2014 it was drafting plans to stop performers who dress up as the characters from appearing in Times Square, where they pose for photos with tourists and then demand tips. (Photo by Eduardo Munoz/Reuters)

Alluvial Fan, China. A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. Image taken by the ASTER instrument on NASA’s Terra satellite on May 2nd, 2002. (Photo by NASA/GSFC/USGS EROS Data Center)

Pakistani female police commandos attend a training session in Nowshera, near Peshawar Pakistan, Wednesday, February 11, 2015. Authorities formed a Special Combat Unit after Taliban militants stormed a Peshawar school on Dec. 16, 2014 and massacred 150 children and teachers. (Photo by Mohammad Sajjad/AP Photo)