Young people fight for fun with their pillows, during the International Pillow Fight Day at the Place des Grottes, in Geneva, Switzerland, Saturday, April 4, 2015. The annual International Pillow Fight Day takes place in hundreds of cities around the world. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

Members of the “Familia Gladiatoria Carnuntina” fight in the historic amphitheatre during the Roman Festival at the archeological site of Carnuntum in Petronell, Austria, June 11, 2016. (Photo by Leonhard Foeger/Reuters)

Warriors from the Suri tribe in Ethiopia still stage the savage “Donga” battles – even after many fighters have been died from their injuries. Donga stick fights take place after the harvests, the Surmas count days owing to knots on a long stem of grass or jags on the trunk of a tree dedicated to that specific use. Here: A tribeswoman sporting a huge lip plate and wearing a skinned animal carcass on her head. (Photo by Eric Lafforgue/Exclusivepix Media)

Jazmin, 6, sister of Jose Luis, receives Isoniazid Preventive Therapy in Carabayllo in Lima, Peru July 14, 2016. At least 30,000 Peruvians are infected with tuberculosis, an ancient disease that killed 1.8 million globally last year, more than AIDS-related and malaria deaths combined. Partners in Health, a Boston-based non-profit that works with Peru's health ministry, offers a simple solution. It trains community volunteers to tend to tuberculosis sufferers in their homes – ensuring patients take medicine daily and helping them navigate the public health bureaucracy. (Photo by Mariana Bazo/Reuters)

Toby, an 11-year-old German shepherd-husky mix, can hold almost anything on his head that his owner, Pat Langner, can think up, including balls, Christmas trees, and even the ingredients for a peanut butter and jelly sandwich. He also shows remarkable self-restraint by not immediately gobbling down the food that his owner gives him to balance. Here: Toby balances halloween decorations on his head. (Photo by Pat Langer/Caters News Agency)

Sophie and Sarah, old English sheepdogs, watch the sea from their plastic chairs. Amateur photographer Cees Bol, from the Netherlands, documents the lives of his beloved pooches Sophie and Sarah by taking pictures of them every day. (Photo by Cees Bol/Caters News Agency/Mercury Press)

Three pugs peer out from a car window in Los Angeles, California. A wacky photographer has come up with an unusual pet project – snapping ecstatic dogs as they hang their heads out of car windows. Lara Jo Regan, 48, embarked on the odd task for her new 2014 calendar “Dogs In Cars”. The unusual shoot, which took place in Los Angeles, California, aimed to explore the joy experienced by pugs and huskies when a breeze hits their faces. (Photo by Lara Jo Regan/Barcroft Media)