The tunnel was built as part of the West Side Line, a freight corridor that once delivered goods to the warehouses and factories lining Manhattan's western edge. By 1980, trucking had won the transportation war, and the last regular freight trains rolled through. The enormous man-made caverns sat empty -- dark, quiet, and ignored by the city above. Homeless people discovered them almost immediately. By the early 1990s, nearly a hundred residents had established a community in the tunnel's southern reaches, near what was then the 60th Street Yard. Some had tapped into power lines, running pirated electricity to improvised shelters. Retired train cars, permanently parked in the tunnel, became walls and roofs. A tent city grew in the large open area at the south end, with hundreds of dwellers at its peak. It was bleak, dangerous, and -- for those who lived there -- preferable to the alternatives.

The tunnel's isolation made it irresistible to graffiti artists. With no police patrols and no foot traffic, painters could work for hours or days on a single piece. The tunnel offered something no wall above ground could: natural spotlighting. Grates in the sidewalks of Riverside Park admitted columns of light that descended into the darkness, illuminating sections of wall like exhibits in a gallery. Artists learned to center their work beneath these shafts, so the paintings seemed to glow in the surrounding gloom. After the 1987 book Spraycan Art by Henry Chalfant and James Prigoff brought attention to the space, painters flocked to the tunnel through broken gates near 103rd Street. Among the earliest were the duo Sane Smith, along with Ghost, Twist, Dan Plasma, Cost, and Revs. Chris "Freedom" Pape created some of his most ambitious murals on the tunnel walls, including a Third of May piece that suffered major water damage around 2010 from a leak overhead.

On April 4, 1991, the tunnel reopened for Amtrak's Empire Connection service. What followed was swift and final. The shantytowns were bulldozed, the entrance gates chained shut, and the residents scattered to other corners of the city. The documentary Dark Days, filmed by Marc Singer in the mid-1990s, captured the community in its last years -- the ingenuity of the dwellings, the routines, the bonds formed underground. Anthropologist Teun Voeten spent extensive time among the tunnel's residents and published the detailed Tunnel People in 2010. Jennifer Toth's 1993 book The Mole People also described the community, though researcher Joseph Brennan later cataloged numerous inaccuracies and embellishments in Toth's account. Freedom himself dedicated a mural to the displaced residents, a gesture of remembrance painted on the walls that had once been their home.

The trains run through the Freedom Tunnel again now, and Amtrak Police periodically escort out the graffiti artists and urban explorers who still find their way in. North of 91st Street, Amtrak never finished repainting the tunnel walls, and every surface that was repainted has since been covered by new layers of graffiti. The tunnel remains a living palimpsest -- each generation of painters adding to and covering what came before. The southern end, once the open yard where the tent city stood, was covered over during the construction of the Trump Riverside development. What was once a frontier has been sealed. But the tunnel persists beneath Riverside Park, carrying commuters who will never see the murals flickering in the grate-light above the tracks, or know that a community once made its home in the dark below their feet.