Smack in the middle of the northern half of Times Square there is a glass booth that sells tickets for Broadway shows. The scene is lit at all hours by hundreds of neon signs, news tickers and depictions of giant M&Ms climbing over Manhattan landmarks.

Stand by the ticket booth this week and glance across the street. Plastered to the side of the Doubletree Hotel, you’ll see an ad for a new ABC television show, digital posters for Broadway staples. Look east and you’ll see a 54-foot tall, 48-foot wide sign, that says, “Did you know a 3rd tower fell on 9/11?”

As the world marks the twelfth year since the September 11, 2001, terror attacks, a campaign called the ReThink911 Coalition is drawing attention to one of the lesser-known events of that day–the collapse of World Trade Center Building 7. Prior to the Sept. 11 Attacks, 7 World Trade Center was a 47-story building just north of the Twin Towers. When the North Tower collapsed, debris hit Building 7, igniting a fire that burned out of control over the course of the day. At 5:21 pm, nearly seven hours after the North Tower came down, 7 World Trade Center crumbled quickly to the ground.

“The heat from the uncontrolled fires caused steel floor beams and girders to thermally expand, leading to a chain of events that caused a key structural column to fail,” the NIST concluded. “The failure of this structural column then initiated a fire-induced progressive collapse of the entire building.”

In 2006, Richard Gage, a San Francisco-based architect, founded Architects and Engineers for 9/11 Truth, which doubts Building 7 collapsed because of fire. Gage and other architects and engineers argue that 7 World Trade Center came down in a free fall, which could only have been cause by a deliberate demolition explosion. More than 2,000 architects and engineers have signed a petition calling for a new investigation into the building’s collapse.

The Sept. 11 attacks were barely over when the first conspiracy theories began to emerge. Some argued that the Pentagon wasn’t hit by a commercial jet, but rather a cruise missile; others contended that the Air Force shot down Flight 93; some even argued that the entire attack was staged as a pretext for war and scaling back civil liberties. Such views have always been in the minority, but, according to polling, were closer to the mainstream than perhaps most Americans imagined. Five years after the attacks, a Scripps-Howard poll found that 16 percent of Americans thought it somewhat or very likely that explosives brought the towers down. More than a third of those surveyed thought it was somewhat or very likely that the government knew about the attacks and took no action to prevent them. Between 2006 and the 10th anniversary of the attacks, that number waned. In August 2011, a poll taken for a BBC documentary found that 15 percent of Americans still believed that the government was involved in the tragedy, while 68 percent rejected a conspiracy.

Gage’s organization has continued campaigning while many other groups have retreated from view. Architects and Engineers for 9/11 makes up large part of the ReThink911 coalition, which spent $44,000 to put the billboard in Times Square at the heart of midtown Manhattan this week. The group says it raised $225,000 from more than 2,00 donors, the majority of whom gave contributions of less than $100. They’re using the money to put up signs and billboards in seven American cities. They will be advertising in Vancouver, Toronto, London and Sydney too.

The nearly quarter million dollar campaign is well within the reach of the coalition. According to Architects and Engineers for 9/11 Truth’s IRS filings as a non-profit organization, the group took in $288,893 in contributions and grants in 2011, the latest year for which filings are publicly available. With an additional $180,464 in program service revenue–money an organization charges for services–giving the organization a total revenue f $469,362. City Outdoor, the owner of the billboard, said that the four-week rate to rent the space is $80,750. The company would not comment on whether it has considered rejecting the advertisement.