Baseball cap manufacturer New Era held an event at the MLB Fan Cave on Wednesday, May 29, to promote its Diamond Era collection of hats. But before they could talk about what's new, Erik Strohl of the National Baseball Hall of Fame in Cooperstown explained how we got here. Strohl brought five historical caps to the Fan Cave that track the evolution of the baseball cap. The five hats represented more than 140 years worth of baseball -- and design -- history. And they highlighted how the baseball cap has gone from on-field equipment to off-field fashion statement. "This is perhaps the most ubiquitous piece of clothing in American culture," Strohl said. "It's come from off the field and into almost every aspect of life.