“Monorail Subway, Capitol To Senate. The Car. Senators Swanson And Townsend As Passengers, 1916”. (Photo by Harris & Ewing Collection). (Please click to enlarge)

Participants in the 18th Annual “No Pants Subway Ride” travel in the subway on January 13, 2019 in New York. The “No Pants Subway Ride” is an annual event started in 2002 by Improv Everywhere in New York, the goal of which is for riders on the subway train to dress in normal winter clothes without pants while keeping a straight face. (Photo by Johannes Eisele/AFP Photo)

A girl rides on a train as she takes part in the first edition of the No Pants Subway Ride in Bucharest, Romania, Sunday, January 11, 2015. The No Pants Subway Ride is an annual which was started in 2002 by Improv Everywhere in New York, the goal is for riders to get on the subway train dressed in normal winter clothes without pants and keep a straight face. (Photo by Vadim Ghirda/AP Photo)

A passenger without pants waits for the subway train during “The No Pants Subway Ride” in Mexico City January 11, 2015. The event, the fifth organized in Mexico, is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Edgard Garrido/Reuters)

NYC no pants subway ride. Thousands of straphangers took their pants off for the 15th annual "No Pants Subway Ride" hosted by Improv Everywhere. People gathered at seven meeting points throughout the five boroughs at 3PM. All participants met up at Union Square around 5PM to and had a pant-less celebration and the afterparty at Webster Hall. (Photo by Paul Martinka/The New York Post)

New York City policemen tangled with demonstrators at a subway station on the opening day of the New York World's Fair, April 22, 1964. Youths attempted to stall the train, which was headed from the city to the fairgrounds, as a form of protest on behalf of civil rights for blacks. (Photo by Charles Gorry/AP Photo)

Pantless people stand on a subway platform 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 Timothy A. Clary/AFP Photo)

People make pictures in a Soviet-era vintage subway car, with a Soviet railways emblem on the side of it, parked in the Partizanskaya subway station in Moscow, Russia, Friday, May 15, 2015. Vintage Soviet-era metro cars were exhibited at the Partizanskaya subway station as part of festivities marking the 80th anniversary of the Moscow subway on Friday. (Photo by Pavel Golovkin/AP Photo)