Young Buddhist novice monks play at a Tibetan nomadic summer grazing area on July 24, 2015 on the Tibetan Plateau in Yushu County, Qinghai, China. Tibetan nomads face many challenges to their traditional way of life including political pressures, forced resettlement by China's government, climate change and rapid modernization. The Tibetan Plateau, often called “The Roof of the World”, is the world's highest and largest plateau. (Photo by Kevin Frayer/Getty Images)

“If a man insisted always on being serious, and never allowed himself a bit of fun and relaxation, he would go mad or become unstable without knowing it”. – Herodotus. “You can discover more about a person in an hour of play than in a year of conversation”. – Plato. Photo: Mandalay, Burma. (Photo by Steve McCurry)

A group of dust covered child labourers gather for a portrait in the brick kiln in Kathmandu Valley, Nepal, 22 February 2015. Bleak photos identify the children working their fingers to the bone in Nepalís brick kilns. Photographer Jan Mˆller Hansen documented the conditions of the brick kilns in Kathmandu Valley, Nepal between 2013 and 2016 while he lived and worked in the area. Jan estimates between 150,000 and 175,000 people are employed in the 200 brick kilns littering the Kathmandu Valley. (Photo by Jan Moeller Hansen/Barcroft Images)

Two holidaymakers amuse themselves with a porter's trolley whilst waiting for their train at Euston Station, London, 5th August 1939. (Photo by A. J. O'Brien/Fox Photos/Getty Images)

A child dressed as a Roman centurion poses during a parade to mark the anniversary of the foundation of Rome in 753 BC, on April 23, 2017 in Rome. (Photo by Alberto Pizzoli/AFP Photo)

In this Sunday, May 29, 2016 photo, fighters take a selfie while firing artillery during fight against Islamic State militants in Fallujah, Iraq. Iraqi forces this week pushed into the city's southern sections after securing surrounding towns and villages more than 50,000 people are believed to be trapped inside the Sunni majority city, about 65 kilometers (40 miles) west of Baghdad. (Photo by Anmar Khalil/AP Photo)

Performers dressed as Pikachu, the popular animation Pokemon series character, perform in the Pikachu parade in Yokohama on August 7, 2016. Some 50 life-size Pikachu characters, the most famous from the Pokemon game, marched along the city’s waterfront street as visitors took mobile phone pictures and videos of them in scorching sunshine. Some participants said they attended the event to search for rare characters of Pokemon – a word short for “pocket monster” – for the megahit smartphone app, which was launched in several countries around the world last month. (Photo by Kazuhiro Nogi/AFP Photo)

A woman talks to a man as two children play inside a wrecked car at a camp for displaced people in Port-au-Prince, Haiti, March 6, 2016. (Photo by Andres Martinez Casares/Reuters)