What you are seeing in the picture above is not a photo of people completely unaware of their surroundings, it is an effort to celebrate a day to get undressed and ride the subway.
The “No Pants on the Subway” day was started in New York, and spread throughout major cities around the globe.
Although until now this special day has been celebrated on the first Friday in May, so that people do not to freeze on the ride, this year the date was moved to winter.
On Sunday, January 13, commuters in London, Berlin, Stockholm and New York all joined and basically took their pants off. For the 13th annual celebration, they made an effort to act perfectly regularly as they got on the subway in their underwear.
The goal is to keep a straight face, which is why pictures of the event, relayed by Daily Mail, reveal no expression of shock or embarrassment on the participants' faces.