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

Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014. A rush-hour subway train derailed in Moscow Tuesday, killing 20 people and injuring at least 150, emergency officials said. Several cars left the track in the tunnel after a power surge triggered an alarm, which caused the train to stop abruptly. (Photo by Ivan Sekretarev/AP Photo)

Commuters walk up the redesigned subway stairs at the Tanjong Pagar subway station on August 23, 2011 in Singapore. The subway stairs have been repainted in bright colours and slogans encouraging people to take the stairs, by way of promoting fitness in the city. (Photo by Chris McGrath/Getty Images)

A professional bull rider participates in a bull riding exhibition at the premiere of “The Longest Ride” at the TCL Chinese Theatre on Monday, April 6, 2015, in Los Angeles. (Photo by Chris Pizzello/Invision/AP Photo)

Russian President Vladimir Putin (R) looks through a window of a research bathyscaphe while submerging into the waters of the Black Sea as he takes part in an expedition near Sevastopol, Crimea, August 18, 2015. (Photo by Alexei Nikolsky/Reuters/RIA Novosti/Kremlin)

In this December 19, 2014 photo, a man stands beside his 1957 Chevrolet Bel-Air car in Havana, Cuba. U.S. car sales have been banned in Cuba since 1959. Cubans have been have been forced to patch together Fords, Chevrolets and Chryslers that date back to before Fidel Castro's revolution which can make it appear like the country is stuck in a 1950s time warp. Since the Communist economic system isn't likely to change soon, many of those cars will have to stay on the road for years. (Photo by Desmond Boylan/AP Photo)

Cool rider Ace on the back on the motorbike, on January 12, 2015, in Surabaya, Indonesia. A pair of dogs enjoy a bit of bark-and-ride – as they weave through Indonesiaís traffic on the back of a motorcycle. Wearing red-framed sunglasses and a helmet the two golden retrievers happily sandwich their owner on the fast bike. Unsurprisingly, the sight of the docile dogs hitching a fast ride in Surabaya, Indonesia, attracts a lot of attention from onlookers. Ace and Armani have been riding since they were just a few months old and now at the age of three the pair jump onto the bike whenever they think their owner is heading out. (Photo by Jefta Images/Barcroft Media/ABACAPress)

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)