A man dressed in a traditional Perchten costume and mask performs during a Perchten festival in the western Austrian village of Huben November 22, 2014. Each year in November and January people in the western Austria regions dress up in Perchten (also known in some regions as Krampus or Tuifl) costumes and parade through the streets to perform a 1,500 year-old pagan ritual to disperse the ghosts of winter. (Photo by Dominic Ebenbichler/Reuters)

History enthusiasts dressed as soldiers fight during the re-enactment of Napoleon's famous battle of Austerlitz near the southern Moravian town of Slavkov u Brna November 29, 2014. Hundreds of history enthusiasts took part in the re-enactment of the battle to mark its 209th anniversary. (Photo by David W. Cerny/Reuters)

A humanoid robot named “Yangyang” shows a facial expression during its demonstration at the Global Mobile Internet Conference (GMIC) 2015 in Beijing, China, April 29, 20155. The android was produced jointly by China's Shanghai Yangyang Intellegent Robot Science Service center and Japanese professor Hiroshi Ishiguro, with the aim of popularising robotics among the young. (Photo by Kim Kyung-Hoon/Reuters)

A protester sprays paint on the window of a bank during a rally against Expo 2015 in Milan, Italy, April 30, 2015. The Milan Expo will open in the city on May 1. Officials are counting on some 20 million visitors to the six month-long exhibition of products and technologies from around the world. (Photo by Stefano Rellandini/Reuters)

An altar is pictured after it was decorated by the Antar family with some 3,000 traditional cheese and corn buns called “chipas”, in celebration of Kurusu Ara in Asuncion May 3, 2015. Kurusu Ara, the Day of the Cross, is a Catholic festival that is combined with local Gurani culture and falls annually on May 3. Paraguayans typically celebrate the festival with chipas, used to decorate religious shrines and altars. The chipas are later distributed to attendees. The buns at the top are arranged to read, “March 3 live”. (Photo by Jorge Adorno/Reuters)

Two attendees compete in the biggest vape cloud competition at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. According to new research provided to Reuters, youngsters say that performing tricks is one of the top two reasons they began using e-cigs. (Photo by David Becker/Reuters)

These adrenaline-junkie climbers go to extraordinary lengths, and heights, to take a selfie. Hundreds of metres above the ground, the climbers risk their life and liberty as they scale huge structures and photograph the results. Known as urban exploration, the aim is to find extremely high and almost inaccessible city buildings and reach their dizzying summits. (Photo by Yaroslav Segeda/Solent News)

Auto worker Christopher Brower screws a component into the cab of a four-door F150 at Ford's Kansas City Assembly Plant where new aluminum intensive Ford F-Series pickups are built in Claycomo, Missouri May 5, 2015. (Photo by Dave Kaup/Reuters)