Arrowhead Stadium is home to the National Football League's Kansas City Chiefs.  It opened in 1972 as a part of the Truman Sports Complex that also includes Ewing Kaufmann Stadium, home of baseball's Kansas City Royals (featured in an April 2nd AAA blog entry).

In October 2013, more than 76,000 Chiefs fans in Arrowhead Stadium set a Guiness Book of World Record for loudest crowd roar at an outdoor stadium.  The legend of the 137.5 decibel roar is recounted below.

http://youtu.be/lHo0QTUgLwg