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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
(03 of24)
Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
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Open Image ModalNo Pants Day 2013, London, Britain - 13 Jan 2013. Commuters on the London Underground not wearing any trousers as part of the annual 'No Pants Day'. (Credit: Rex)
(08 of24)
Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
(09 of24)
Open Image ModalParticipants in the annual "No Pants Subway Ride" ride a train in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalCarrying a bike, a participant in the annual "No Pants Subway Ride" transfers to another train in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalA soldier takes off his pants while riding the subway on January 13, 2013 in New York City. He and thousands of others participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image ModalPeople ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image ModalParticipants in the annual "No Pants Subway Ride" ride a train in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image Modal People ride the subway pantless on January 13, 2013 in New York City. Thousands of people participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon winter event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image ModalParticipants in the annual "No Pants Subway Ride" transfer to another train at a subway station in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalParticipants in the annual "No Pants Subway Ride" wait to get a train at a subway station in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalParticipants in the annual "No Pants Subway Ride" wait to get a train at a subway station in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalParticipants in the annual "No Pants Subway Ride" ride a train in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)
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Open Image ModalA soldier takes off his pants while riding the subway on January 13, 2013 in New York City. He and thousands of others participated in the 12th annual No Pants Subway Ride, organized by New York City prank collective Improv Everywhere. During the afternoon event, participants boarded separate subway stops and removed their pants, pretending that they did not know each other. The event, refered to as a "celebration of silliness" is designed to make fellow subway riders laugh and smile. (Photo by John Moore/Getty Images)
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Open Image ModalA man, wearing underwear, records video of another man, also wearing underwear, during the annual "No Pants Subway Ride" at a subway station in Mexico City, Sunday, Jan. 13, 2013. (AP Photo/Marco Ugarte) (credit:AP)