Blue, white and red brassieres, the colours of the French national flag, hang from a balcony in Marseille, France, November 27, 2015 as the French President called on all French citizens to hang the tricolour national flag from their windows on Friday to pay tribute to the victims of the Paris attacks during a national day of homage. (Photo by Jean-Paul Pelissier/Reuters)

A Hindu devotee ululates as she holds a banana tree trunk after taking a dip in the waters of the Ganges river during a ritual as part of the Durga Puja festival in Kolkata, India, September 27, 2017. (Photo by Rupak De Chowdhuri/Reuters)

A herder stops for reindeers to have a rest while riding along the tundra area in Nenets Autonomous District, Russia, November 27, 2016. In Russia's remote Arctic regions reindeer herding has been a way of life for centuries. Each winter herders in Russia's sparsely populated Nenets Autonomous District corral their reindeers into open-air pens before selecting weak animals to be culled... (Photo by Sergei Karpukhin/Reuters)

Aerobatic aircrafts fly during a performance at the Airshow Zhengzhou 2017 in Zhengzhou, capital of central China's Henan Province on April 27, 2017. The 5-day air show kicked off in Zhengzhou on Thursday, aiming to build a general aviation gathering center for business and communications. (Photo by Li An/Xinhua via ZUMA Wire)

A bonnet macaque sits on consecrated idols of snakes as it drinks milk offered by a devotee during the Hindu festival of Nag Panchami, which is celebrated by worshipping snakes to honour the serpent god, inside a temple on the outskirts of Bengaluru, India, July 27, 2017. (Photo by Abhishek N. Chinnappa/Reuters)

Yanna Xian, 24, and her boyfriend Mitch Brown, 27, were swimming while on a boat tour off Honolulu, Hawaii last year, when a curious two-week-old humpback approached them. (Photo by South West News Service)

A demonstrator wears a message on a t-shirt in Tahrir Square on May 27, 2011 in Cairo, Egypt. The ruling Supreme Council of the Armed Forces said that there would be no use of violence against protests dubbed “the Second Revolution of Anger” taking place in Cairo and other cities in Egypt. (Photo by Peter Macdiarmid/Getty Images)

Wladimir Klitschko (L) and David Haye attend a press conference on June 27, 2011 in Hamburg, Germany to preview the heavy weight title fight between them which will be held on the 2nd July 2011 at the Imtech Arena. (Photo by Scott Heavey/Getty Images)