Sesame Street got rezoned for pay TV a decade ago. Reading Rainbow relocated to YouTube last year. Even American Experience — winner of 30 Emmys over its 37-year history — was recently swept into the dustbin of history (or at least suspended production for nine months).

These are, to be sure, dark, dark days for PBS, with the Corporation for Public Broadcasting dissolving itself in January — after Congress shut off its funding — sending devastating budget cuts rippling through the entire public broadcasting network, forcing some stations, like New Jersey’s WNJN, to shut down entirely.

And yet, despite it all, one modest little cathode-tube relic that’s been beaming into households since the dawn of educational TV — Richard Heffner’s The Open Mind, the gleefully eggheaded talk show on which Martin Luther King Jr gave his first sit-down televised interview — continues to soldier on. Indeed, the program just passed its 70th anniversary, making it the longest-running PBS show in history.

“My grandfather wanted to bring intellectual firepower to discussions of public policy,” notes Alexander Heffner, who took over as host after Richard’s death in 2013. “He wanted there to be a platform on early television that offered something other than bandits and robbers.”