​Think of it as a supersized Mount Rushmore. With an awfully heavy presence from America’s Team.CBS Sports has revealed its list of the 20 greatest head coaches in NFL history, with three of them- 15% of the entire collection- having roamed the Cowboys sidelines during their legendary careers.AdvertisementAdvertisementAdvertisementThe list goes all the way back into the league’s 100-plus-year history with notable figures like Curly Lambeau, George Halas, and Paul Brown, and will even lead plenty of today’s fans scrambling for Google to discover who Guy Chamberlain was. The NFL’s golden age of the late 1950s-to-1960s is also well-represented with names like Weeb Ewbank, Hank Stram, and- of course- Vince Lombardi. But plenty of modern-era coaches have recently put indelible marks on the game, too: Tony Dungy, Mike Shanahan, Andy Reid, and Bill Belichick, who tops the rankings at No. 1.As for the Cowboys? Tom Landry, Jimmy Johnson, and Bill Parcells account for a whopping 328 combined regular-season wins. That’s 57% of the total regular-season wins for the franchise across its entire history. And to further drive home how significant these men were to the organization, their 27 postseason victories comprise 75% of the Cowboys’ all-time playoff wins (and that’s just Landry and Johnson; Parcells never notched a postseason win while in Dallas).Here’s how each of the three placed in the CBS rankings.112599 Cowboy owner Jerry Jones and Dolphins coach Jimmy Johnson meet before the Thanksgiving Day game in Dallas.”Few coaches have been as impactful in the NFL’s modern era as Johnson, who, in just three years,” CBS notes, “took the Cowboys from 1-15 to Super Bowl champions.” That’s obviously just part of Johnson’s legacy. His story can’t be told without also bringing up the Super Bowl repeat in 1993… and how it all came after he orchestrated a total roster rebuild unlike any that had ever been seen.AdvertisementAdvertisementAdvertisementFrom the Herschel Walker trade to creating the revolutionary draft value chart that is still used in some form by every team today to managing a locker room full of some of the most outspoken, colorful, and even notorious characters to ever play the game, Johnson built a dynasty and changed the sport, all with no prior NFL experience whatsoever.Two of the six CBS writers who created the list had Johnson ranked 14th, two had him at No. 15, one placed him 17th, and one left him off the list entirely.This file photo from 2005 shows Cowboys coach Bill Parcells, left, on the sideline with coach Sean Payton during a game against the Eagles at Texas Stadium in Irving, Texas on Oct. 9, 2005.”If you need a coach to jumpstart your franchise,” CBS suggests, “Bill Parcells is your guy. Four times during his Hall of Fame career, Parcells turned a struggling team into a contender in short order.”AdvertisementAdvertisementAdvertisementThat’s precisely what happened in 2003, when Jerry Jones convinced Parcells to come out of retirement to