A Sikh warrior, wearing a huge turban attends the annual fair of “Hola Mohalla” in Anandpur Sahib, in the northern Indian state of Punjab, Monday, March 17, 2014. Believers from various parts of northern India collect at the religious fair to celebrate the festival of Holi in a tradition set by the tenth Sikh guru Guru Gobind Singh in the seventeenth century. Nihangs, or Sikh warriors, display their martial skills and attire during the fair, believed to be maintained in the exact tradition as set by the Guru. (Photo by Altaf Qadri/AP Photo)

Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)

A person dressed as an astronaut walks past a man stopping traffic on a pedestrian crossing outside the Sydney Exhibition Centre September 13, 2014 where the science-fiction convention called “Oz Comic-Con” is currently being held. The two-day convention showcases “pop culture”, and includes appearances by actors from science-fiction movies and television shows. (Photo by David Gray/Reuters)

Faruk, 17, a Rohingya refugee trader holds betel leaves which are on sale at a stall in Palong Khali refugee camp near Cox's Bazar, Bangladesh, November 3, 2017. He left his village in Myanmar when the military opened fire towards the Rohingya. “I buy this betel leaf from Palong Khali market, in one bundle there are 160 pieces, I buy it for 80 taka and I sell it for 100 taka (1 Bangladeshi Taka = 0.012 US Dollar). Bangladeshi's and I sell for the same rate in the camp. Outside in the local market it is 80 taka per bundle. My problem is that I don't have money so I can't buy anything to eat, I can't buy fish to eat”, he said. (Photo by Hannah McKay/Reuters)

A young Thai man jumps in the air and cheers as his rocket takes off at the Bun Bang Fai Rocket Festival on May 10, 2015 in Yasothon, Thailand. (Photo by Taylor Weidman/Getty Images)

A person poses on the track during a fashion competition at the Durban July horse racing event in Durban, South Africa, July 2, 2016. (Photo by Rogan Ward/Reuters)

Students celebrate their A-level results at King Edward VI High School for Girls in Birmingham, England on August 18, 2016. The proportion of top grades achieved by A-level students across the UK has fallen for a fifth year in a row, and girls have caught up with boys in attaining A* grades. (Photo by Joe Giddens/PA Wire)