On August 13, 1979, the uncompleted roof of the Rosemont Horizon collapsed, killing five construction workers and injuring 16 others.[5] The collapse was featured in the “Engineering Disasters” episode of Modern Marvels, first broadcast by The History Channel on April 20, 2006.

The wooden roof of the 20,000-seat arena was 90 percent complete when it suddenly collapsed. Shortly after the collapse, officials speculated about a low-flying aircraft causing the collapse, and Rosemont Mayor Donald E. Stephens told the AP that it was probably a gust of wind. However, an Occupational Safety and Health Administration investigation revealed, “The building was in such unstable condition that anything could have set off the collapse. You could have blown on it and knocked it down.”

According to an engineering case studies project, shoddy planning and missing bolts are what caused the unfinished roof to collapse.

A post-collapse investigation carried by the Occupational Safety and Health Administration revealed that the cause of the collapse was the unstable condition of the wood roof frame. Over 53 percent of the required connection bolts were missing from the building’s roof. Of the 944 girder bolts required for the connections already installed, only 444 were in place. Of these, 338 had no nuts, and some of the nuts in place were only finger-tight. OSHA also discovered that only 27 percent of the “compensating steel plates” were properly installed. Although the missing bolts were found the triggering cause, it was proved that inadequate bracing and the stockpiling of materials in the roof contributed to the collapse. Several other violations were attributed to the roof erector, who was severely fined by OSHA. The project’s architect and other subcontractors were also fined for diverse irregularities. Even the independent engineering firm retained by the city to investigate the collapse was fined by OSHA for unnecessarily exposure of their employees to fall hazards during field inspection.

In an interesting note, one year after the roof collapse, concrete stands under construction also collapsed at the Rosemont Horizon, dumping 34 tons of concrete to the ground. No fatalities or major injuries resulted from this accident.

The tragedy was featured on the History Channel’s Engineering Disasters in 2004, if you’d like to learn more.

The facility, originally named Rosemont Horizon, was intended to be the home of the Chicago Horizons of the Major Indoor Soccer League (MISL) and was home of the 1980-1981 season but the franchise folded in 1982. It was also intended to be the home of the WHA’s Chicago Cougars, but the team folded in 1975, three years before construction on the arena started. The first concert held at the Horizon was Fleetwood Mac on May 15, 1980, as they cut a red ribbon on the stage during the opening of the show.

The Rosemont Horizon was featured in many music videos, including the 1985 music video “Big City Nights” by Scorpions.[6]

Insurance company Allstate signed a 10-year contract worth more than $10 million on June 9, 1999, to acquire naming rights to the arena and renovate it.[7]

On December 29, 2002, Creed had an infamous concert at the arena, where the lead singer Scott Stapp had a bad reaction with a combination of pills and alcohol, causing Stapp to be inebriated during the concert. After mumbling incoherently for 5 songs, he later fell asleep and after a few minutes woke up and continued to sing until the concert was ended early. This resulted in a $2 million lawsuit against the band.[8]

On December 14, 2003, the floor at the Allstate Arena was named “Ray and Marge Meyer Court” in honor of Basketball Hall of Famer Ray Meyer and his wife. Meyer coached DePaul’s men’s team for 42 seasons and is the school’s all-time winningest coach.