A weeping South Vietnamese mother and her three children are shown on the deck of this amphibious command ship being plucked out of Saigon by U.S. Marine helicopters in Vietnam, April 29, 1975. (Photo by AP Photo)

An artist from the state of Telangana reacts to the camera as they wait for their turn to perform during a media preview displaying a glimpse of culture of different parts of India, in New Delhi, India, Thursday, January 22, 2015. The tableaux will be part of the Indian Republic Day parade on Jan. 26. (Photo by Altaf Qadri/AP Photo)

A visitor holds up her toy bunny to the aquarium glass in front of Aurora the Russian polar bear at the Sao Paulo Aquarium in Sao Paulo, Brazil, Thursday, April 16, 2015. (Photo by Andre Penner/AP Photo)

A fishing boat that was ran aground by the sea while moored in the port of Coquimbo, some 445 km north of Santiago, during the eve's earthquake on September 17, 2015. A million people were evacuated in Chile after an 8.3-magnitude quake struck offshore in the Pacific, killing at least 10 people and triggering tsunami waves along its northern coast. (Photo by Martin Bernetti/AFP Photo)

A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

World War Two veteran Abla Begaliyev, 91, is seen in an undated handout picture (L), poses for a picture in Arashan (Top R) and at home in Kyrgyzstan April 14, 2015. Begaliyev served in the border guard cavalry from February 1942 until April 1947. Originally from Kyrgyzstan, he fought on the Ukrainian front and relocated to the border with Afghanistan at the end of World War Two. As the world marks the 70th anniversary of the end of World War Two, Reuters photographers the length and breadth of the former Soviet republics (CCCP) captured portraits of Red Army veterans, mostly now in their 80s and 90s, today and through archive pictures at the time. More than 20 million Soviet citizens were killed in the war. (Photo by Vladimir Pirogov/Reuters/Family handout (L))

China Airlines stewardess Wang Wen Hwang leaps from the burning China Airlines plane after assisting the passengers to safety February 27, 1980. Miss Wang saved most of the lives of the passengers despite her injuries. She was the last to leave the planes. (Photo by AP Photo)

People watch as workers inflate a near-10 metre high giant spider by Singaporean artist Jackson Tan in Singapore's Marina Bay financial district on February 6, 2017. The spider is one of several inflatable creatures that will form the Art-Zoo, a section created by Singaporean artist Jackson Tan for the iLight Marina Bay annual light-art festival in the city-state. (Photo by Roslan Rahman/AFP Photo)