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)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)

Revellers pose during the 24th Street Parade dance music event in Zurich, August 29, 2015. (Photo by Arnd Wiegmann/Reuters)

A reveller is tossed into the air as they celebrate the Holi spring festival in Kathmandu on March 12, 2017. The “Holi” festival of colours is a riotous celebration of the coming of spring and falls on the day after the full moon in early March every year. (Photo by Prakash Mathema/AFP Photo)

A reveller takes part in the Gay Pride Parade in San Salvador, on June 24, 2017. (Photo by Marvin Recinos/AFP Photo)

BASE jumper Luke Denniss of Australia gestures as he dives in the air from the Kuala Lumpur Tower during the KL Tower International Jump in Kuala Lumpur, Malaysia, Saturday, September 27, 2014. BASE stands for the places such jumpers usually jump from: buildings, antennas, spans (bridges) and earth (cliffs). (Photo by Lai Seng Sin/AP Photo)

A Thai visitor appears to be frightened by a life-size Velociraptor model also known as Raptor at the Dinosaur Planet theme park in Bangkok, Thailand, 25 March 2016. The 500 million baht (14 million US dollars or 12 million euro) theme park opening in the Thai capital aimed to attract more than 15,000 visitors a day featuring a chance to experience more than 200 dinosaurs from various species that are brought back to life. (Photo by Rungroj Yongrit/EPA)

Members of ASC Tornados, the motorcycle display team of the Indian army, lie in a row on the ground as another performs a stunt by jumping over them during the 225th anniversary celebrations of Army Service Corps in Bangalore, India, Tuesday, December 8, 2015. The Army Service Corps which was established in 1790 is an arm of the Indian Army which handles its logistic support function. (Photo by Aijaz Rahi/AP Photo)