A demonstrator is detained during May Day rallies in Santiago May 1, 2013. (Photo by Ivan Alvarado/Reuters)

Li Yuming, a local farmer who is interested in scientific invention, works on his unfinished miniature submarine “Xiaguang V” on the outskirts of Wuhan, capital of central China's Hubei province August 24, 2007. “Xiaguang V”, which is 3-metre long, 1.2-metre in height, has a maximum diving depth of 20 metres, and can hold two adults and one child at the same time. The submarine will be used for tour after safety test, local media said. (Photo by Reuters/Stringer)

A member of the mainly Christian “anti-balaka” (anti-machete) militia trains in the Boeing neighbourhood of Bangui, Central African Republic, on February 24, 2014. (Photo by Fred Dufour/AFP Photo)

Monks dressed as Tibetan Buddhism characters attend a religious ceremony, known as “Da Gui” or beating ghost, to celebrate the upcoming Tibetan New Year which starts on March 1 at Yonghegong Lama Temple, in Beijing February 28, 2014. This Tibetan ceremony is held annually at the end of the first lunar month with mask dancing to expel ghosts, according to a press release. (Photo by Jason Lee/Reuters)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)

In this Monday, October 5, 2015 photo, a thick blanket of early morning fog partially shrouds the skyscrapers of the Marina and Jumeirah Lake Towers districts of Dubai, United Arab Emirates. Dubai's rapid transformation from a desert outpost into one of the world's most architecturally stunning cities is mapped out in the Marina. Where just 15 years ago there was empty, flat land, today a bustling neighborhood thrives centered around a canal and an impressive skyline that pierces through the clouds. (Photo by Kamran Jebreili/AP Photo)

Indian Hindu devotees wait to take part in an event to mark Pongal in Mumbai on January 15, 2016. Pongal, which coincides with the Hindu festival Makara Sankranthi, is a thanksgiving and harvest celebrated throughout India and specifically by those from the Indian state of Tamil Nadu. (Photo by Indranil Mukherjee/AFP Photo)