People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People take part in the International Pillow Fight Day at Hong Kong's financial Central district April 4, 2015. (Photo by Tyrone Siu/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

People fight with pillows during International Pillow Fight Day at Heroes Square in Budapest April 4, 2015. (Photo by Laszlo Balogh/Reuters)

Youngsters throw pillows in the air for a photograph after taking part in a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. Romanians took part in large numbers in the pillow fight to mark International Pillow Fight Day. (Photo by Vadim Ghirda/AP Photo)

Feathers fly as youngsters engage in a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. (Photo by Vadim Ghirda/AP Photo)

Feathers fly as people engage in a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. (Photo by Vadim Ghirda/AP Photo)

Youngsters hold pillows in the air for a photograph after taking part in a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. (Photo by Vadim Ghirda/AP Photo)

A man holds a girls hand after a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. (Photo by Vadim Ghirda/AP Photo)

Feathers fly as youngsters engage in a pillow fight downtown Bucharest, Romania, Saturday, April 4, 2015. (Photo by Vadim Ghirda/AP Photo)

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. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

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)

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. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

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. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

People participate in a pillow fight to mark International Pillow Fight Day, Saturday, April 4, 2015, in Toronto. (Photo by Chris Young/AP Photo/The Canadian Press)

People participate in a pillow fight to mark International Pillow Fight Day, Saturday, April 4, 2015, in Toronto. (Photo by Chris Young/AP Photo/The Canadian Press)

People participate in a pillow fight to mark International Pillow Fight Day, Saturday, April 4, 2015, in Toronto. (Photo by Chris Young/AP Photo/The Canadian Press)