Everyone knows about the glory years of the Steel Curtain, but you rarely hear people talk about this:
In 1976, the Steelers got off to a rocky 1-4 start before putting on what may be the most dominant defensive performance in NFL history.
Over the next nine weeks, they held opponents to a combined total of only 28 points, and allowed more than 6 points only once. (Yep....0 TD's allowed in 8 of the 9 weeks.) They pitched shutouts in five of those games, including three in a row at one point, and closed the season with consecutive shutouts.
This was almost certainly the greatest defensive effort of all time; unfortunately, they ended up losing the AFC Championship to Oakland, and their incredible accomplishments that year have now been largely forgotten.