Both novels were inspired by the construction of the World Trade Center in the early-1970s, and what could happen with a fire in a skyscraper. In Richard Martin Stern's novel "The Tower", the fictional 125-story building was set next to the north tower of the World Trade Center. The climax of the novel was centered around a rescue mounted from the north tower.
Against Irwin Allen's strenuous objections, Steve McQueen insisted on doing the stunt where he leaps off a helicopter onto the top of the burning building.
During filming an actual fire broke out on one of the sets and Steve McQueen found himself briefly helping real firefighters put it out. One of the firefighters, not recognizing McQueen, said to the actor, "My wife is not going to believe this", to which McQueen replied, "Neither is mine."
The biggest grossing film of 1974.
After seeing this film, novelist Roderick Thorp had a dream that same night about a man being chased through a skyscraper by gun-wielding assailants. This was the inspiration for his 1979 book "Nothing Lasts Forever" which eventually was made into the film Die Hard (1988).