Marilyn Agrelo is taking us back to “Sunny Days” spent with Elmo, Bert, and Big Bird. The “Mad Hot Ballroom” director’s latest offering, “Street Gang: How We Got to Sesame Street,” pays loving tribute to the groundbreaking show and its enduring legacy.

“This was an experiment. No one had ever seen anything like it,” says “Sesame Street” creator Joan Ganz Cooney in a new trailer for the doc. Children were watching a great deal of television, and Cooney saw an opportunity for the medium to help educate them. The minds behind “Sesame Street” believed that “television could be socially valuable.”

Artists, writers, and educators wanted to “capture the family aura,” but they also viewed “Sesame Street” as a political show. The series supported the civil rights movement and emphasized the importance of equality.

“It felt like the type of story that would seem to be about one thing on the surface — that is, how this TV show was made — but would actually be about something much deeper and surprising,” Agrelo told us. “In fact, the more and more I read about the origins of ‘Sesame Street,’ the more I was blown away by what a cultural revolution it was. How political it was. How groundbreaking. The fact that this was unleashed on the world in the form of a preschool program was amazing and irresistible to me.”

Asked what she’d like people to think about after seeing the doc, the director said, “The civil rights movement and all the unrest, protests, and awakening that occurred in the late 1960s gave birth to ‘Sesame Street.’ Many of these same fights are being fought today. The story of the birth of ‘Sesame Street’ is incredibly relevant at this moment in time. And art can change our world just as powerfully today,” she emphasized.

“Street Gang: How We Got to Sesame Street” made its world premiere at this year’s edition of Sundance Film Festival. The film hits theaters April 23 and video-on-demand platforms May 7.