I am not old enough to remember this ( a few of you may be) but Jonathan Rand has a great article about a pre-season game between the Chiefs and Bears on 23 August 1967.  He writes

For Chiefs fans who are gray around the temples, tonight’s game against the Bears in Chicago should bring back memories of one of the most important pre-season games ever played. Actually, it may have been the only important pre-season game ever played.

The game was the first game the Chiefs played after the NFL-AFL merger (also the first game after we were creamed in Super Bowl I), and the Bears came into Municipal Stadium looking to again prove that former AFL teams were no match for the NFL teams.  They were led by Halas, who vehemently opposed the merger, even going as far as to offer teams to Hunt and Ryan.  We played our starters the whole game and beat the Bears 66-24.  I thought it was a well-written article, a great look back at history, and another reminder of how indebted we Chiefs fans and the whole sport of American Football are to the great Lamar Hunt.

Check it out at the mothership