Fire fighters, emergency service vehicles and a helicopter in Moskovsky Prospekt at the entrance to Tekhnologichesky Institut station of the St Petersburg metro in the aftermath of an explosion which occurred in a train at 14:40 Moscow timeon April 3, 2017. (Photo by Peter Kovalev/TASS)

People spray water in the street ahead of “Songkran”, the annual Thai New Year water-throwing festival, in Kowloon City, Hong Kong, China, 09 April 2017. The pouring of water is a key element in the festival as it represents purification and the washing away of one's sins and bad luck for the year. The event also includes a “Miss Songkran” pageant where contestants are clothed in traditional Thai dress, and a winner is crowned. This year's “Songkran” will begin in Thailand on 13 April 2017. (Photo by Alex Hofford/EPA)

Iraqi paramilitary troops fire towards Islamic State militants during a battle with Islamic State militants on the outskirts of the ancient city of Hatra near Mosul,Iraq April 26, 2017. (Photo by Reuters/Stringer)

Performer from the Mangueira samba school parades during carnival celebrations at the Sambadrome in Rio de Janeiro, Brazil, Tuesday, February 9, 2016. (Photo by Silvia Izquierdo/AP Photo)

An Indian underprivileged bride gets her jewellery adjusted by a relative during a mass marriage ceremony in New Delhi, India, March 10, 2016. Fourteen underprivileged couples tied up the nuptial knot in the mass marriage ceremony organised by various social organisations. (Photo by Rajat Gupta/EPA)

Queen Ashi Jetsun Pema, 21, walks out after the marriage ceremony is completed on October 13, 2011 in Punakha, Bhutan. The Dzong is the same venue that hosted the King's historic coronation ceremony in 2008. The Oxford-educated king is popular in the country and the ceremony will be followed by celebration in the capital and countryside. (Photo by Paula Bronstein/Getty Images)

Samburu women of the Lorubai traditional dance group are seen wearing traditional beaded necklaces during a Peace Marathon for pastoralist communities at the Archers post in Isiolo, Kenya on April 26, 2018. The aim of the event is to bring the warring pastoralist communities of Samburu, Turkana, Borana and others together, and end the rivalry due to scarcity of pasture and water in the region. The peace marathon is organized by Kenya's Northern Rangeland Trust. (Photo by Simon Maina/AFP Photo)

A helicopter from the Venezuela's Army takes part in a military parade to celebrate the 207th anniversary of Venezuela's independence in Caracas, Venezuela July 5, 2018. (Photo by Marco Bello/Reuters)