A group called Improv Everywhere is responsible for the idea.
Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)A soldier removes his pants on the subway 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. (Credit: John Moore/Getty Images) Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Pantless people pose for photos at the Union Square subway station 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. (Credit: John Moore/Getty Images)A pantless man knits at the Union Square subway station 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. (Credit: John Moore/Getty Images) Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)Some riders in the New York City subway in the underwear as the take part in the 2013 No Pants Subway Ride January 13, 2013. Started by Improv Everywhere, the goal is for riders to get on the subway train dressed in normal winter clothes (without pants) and keep a straight face. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)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. (Credit: John Moore/Getty Images) A pantless woman stands at Union Square 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. (Credit: John Moore/Getty Images)
Organizers arranged that starting at 3 p.m., people got on trains at six different stops across the city, took off their pants and put them into their backpack. Participants then acted as if everything was completely normal as they rode on to Union Square.
Participants are asked to don typical winter wear such as coats, hats and gloves and act as if they don't know other pantsless riders, according to organizers.
The group said it was just all in good fun.
"People are willing to give basically their Sunday afternoon to take off their pants; to do something silly and fun, and you know, a good time," one participant said.
"It makes you feel invincible; superior, because nobody else has any idea what's going on," another said.
There were no-pants subway rides in dozens of cities in 17 countries Sunday.
In New York City, participants were happy it was rather warm. In prior years, the cold has bummed them out.
Last year, about 4,000 people went without pants in the New York City subway for the event.
According to Improv Everywhere, the no pants subway ride started as a small prank carried out by seven people but has grown into an international event.
Did you be partake in the no pants subway ride? What do you think of the event? Share your comments below...
