In the early 1990s, three young Americans took what they called a stoner idea to Amsterdam and built something that would quietly reshape American comedy. Boom Chicago, an English-language improv theater planted in a city of international strangers, became an unlikely crucible — one where the inability to rely on shared cultural references forced performers to excavate something more durable: universal human truth. The comedians who passed through its stage, from Seth Meyers to Jordan Peele to the creators of Ted Lasso, carry its fingerprints still.