Passengers not wearing pants prepare for the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. The event is an annual flash mob and occurs in different cities around the world in January, according to its organisers. (Photo by David W. Cerny/Reuters)





Passengers not wearing pants prepare for the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





Passengers not wearing pants wait for a subway during the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





A passenger not wearing pants waits for a subway train during the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





Passengers not wearing pants walk down the stairs during the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





Passengers not wearing pants go by a subway train during the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





Passengers not wearing pants go by a subway train during the “No Pants Subway Ride” in Prague, Czech Republic, January 8, 2017. (Photo by David W. Cerny/Reuters)





People take part in the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





People take part in the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





People take part in the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





People take part in the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. The event is an annual flash mob and occurs in different cities around the world in January, according to its organisers. (Photo by Hannibal Hanschke/Reuters)





People take part in the annual '“No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





People take part in the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





Participants of the annual “No Pants Subway Ride” in Berlin, Germany, January 8, 2017. (Photo by Hannibal Hanschke/Reuters)





A participant without trousers performs during the 2017 No Pants Subway Ride in Toronto, Canada, on January 8, 2017. Hundreds of participants took part in the annual event in Toronto on Sunday. (Photo by Zou Zheng/Xinhua/Sipa USA)





A dressed up participant without trousers takes part in the 2017 No Pants Subway Ride in New York, the United States, on January 8, 2017. (Photo by Zou Zheng/Xinhua/Sipa USA)





People without pants pose for a picture on an icey street during the “No Pants Subway Ride” in New York on January 8, 2017. The event, which first took place in New York in 2002, has become a yearly event attended by people in more than 60 cities across the globe. (Photo by Kena Betancur/AFP Photo)





People without pants travel in the subway during the “No Pants Subway Ride” in New York on January 8, 2017. (Photo by Kena Betancur/AFP Photo)





A man without pants dances in a subway station during the “No Pants Subway Ride” in New York on January 8, 2017. (Photo by Kena Betancur/AFP Photo)





Two pantless women wait for a train at Brooklyn's Jay Street/MetroTech station during the 16th annual No Pants Subway Ride, Sunday, January 8, 2017, in New York. Created in 2002 by Charlie Todd of Improv Everywhere, the group aims to surprise and delight random strangers through positive pranks. (Photo by Kathy Willens/AP Photo)





A passerby, far right, glances as participants in the 16th annual No Pants Subway Ride pose for photographs in their underwear, Sunday, January 8, 2017, in New York after riding pantless in the subway. (Photo by Kathy Willens/AP Photo)





A man studies the map as two pantless women wait for their train along the R line during the annual 16th annual No Pants Subway Ride, Sunday, January 8, 2017, in the Brooklyn borough of New York. (Photo by Kathy Willens/AP Photo)





Three men pose in their underwear in front of a Union Square subway station sign during the 16th annual No Pants Subway Ride, Sunday, January 8, 2017, in New York. (Photo by Kathy Willens/AP Photo)





Two men react as a woman puts her boots back on after removing her pants during the annual No Pants Subway Ride, Sunday, January 8, 2017, in New York. (Photo by Kathy Willens/AP Photo)





A woman without pants travels in the subway during the “No Pants Subway Ride” in New York, on January 8, 2017. (Photo by Kena Betancur/AFP Photo)





Passengers take part in the No Pants Underground Ride in Milan, Italy on January 8, 2017. (Photo by PA Images/Sipa USA)





A man looks at a group of people boarding a train wearing only underpants during the 'No Pants Subway Ride' action in central Berlin, Germany, 08 January 2017. Dozens of people took part in this peaceful activity in order to stand out in a everyday routine. The action takes part in different cities of the world today. No Pants Subway Ride is an annual global event started in New York, USA in 2002. (Photo by Felipe Trueba/EPA)