Police officers detain an opposition protester during a May Day rally in Saint Petersburg, Russia on May 1, 2019. Labor Day or May Day is observed all over the world on the first day of the month of May to celebrate the economic and social achievements of workers and fight for laborers rights. (Photo by Igor Russak/Reuters)

地下セクシーアイドル「ベッド・イン」2ndシングル「♂×♀×ポーカーゲーム」のミュージックビデオ。

A mass pillow fight in Trafalgar Square in central London on April 5, 2014 on International Pillow Fight Day. (Photo by Jane Scanlan)

Children stand in a boat at the banks of the polluted Yamuna River during a dust haze as they wait to give a ride to worshippers in New Delhi during World Environment Day June 5, 2010. (Photo by Reinhard Krause/Reuters)

The British alternative rock duo Nova Twins perform on day three of the 2024 Shaky Knees music festival in Atlanta, US on May 5, 2024. (Photo by John D. Shearer/Rex Features/Shutterstock)

Manchester and Salford University students have been celebrate the last day of freshers week in Manchester, England on September 25, 2016. (Photo by Jordan Sinclair/UK News Pictures)

Kimono-clad women enjoy the view from Tokyo Sky Tree’s 350-meter-high observation deck in Sumida Ward, Tokyo, on the Coming of Age Day, January 9, 2017. Sumida Ward invited about 430 local 20-year-old to the deck to celebrate them. Many city governments invite local 20-years-old to there’s symbolic places and celebrate for their Coming of Age Day. (Photo by The Yomiuri Shimbun via AP Images)