When the founder of Discovery Communications announced last week that he was retiring from the cable programming giant, he was not marking an end as much as signaling his desire to get back to his original passion.

John S. Hendricks started Discovery at the dawn of the cable TV age 32 years ago, with the idea that a channel based on documentaries and nonfiction programming could have a sizable audience. Time has proved him correct, even if the parent company’s collection of shows in recent years , featuring moonshiners, tattoo artists and a child beauty pageant contestant nicknamed Honey Boo Boo, sometimes seems to stretch the genre. Discovery is an international powerhouse with a market capitalization approaching $30 billion; its holdings include not just Discovery but also TLC, Animal Planet, Velocity, a 50 percent interest in Oprah Winfrey’s OWN and more.

Hendricks, though, has never really gotten over the notion that video can be a powerful educator. He is using a relatively small part of the fortune he made from Discovery and starting a company, the Curiosity Project, to create what he calls a lifelong learning academy.

The initiative represents Hendricks’s latest attempt to take people on a deeper dive into the big intellectual questions of our day, in subject areas such as science, technology, civilization and the human spirit.

In an interview this year, Hendricks said he wants to bring in big thinkers to discuss their lofty ideas at pricey, week-long retreats, and then turn those conversations into high-quality video segments that he makes available online and on-demand for, say, $19.99 a year.

He has been quietly putting together this business. Hendricks already owns a massive spread in Colorado, on the Utah border, where he runs a resort that will become home base for his self-styled Curiosity Retreats. And he has taken out office space in Silver Spring, across from Discovery’s headquarters, to create his video-on-demand business.

Hendricks estimates that he might have to sink $5 million into the project over the next five years to gain a foothold, and he is doing so out of his personal venture company, Hendricks Private Holdings. He projects revenue of $1 million in 2014.

He is entering a crowded space. Plenty of colleges and universities are putting their courses online, and entire businesses have been established with the idea of introducing smart people to the masses. (The Washington Post offers learning experiences it calls MasterClass). And Web sites such as YouTube offer a wealth of educational fare free.

But Hendricks has been pursuing this dream for a long time, since he was an undergraduate at the University of Alabama on a work-study assignment to support faculty members’ course needs. The campus job involved ordering books or films and other supplementary materials. In his autobiography, “A Curious Discovery,” he recounts how he spent down time scanning “inch-thick catalogs of educational films” from the likes of Encyclopedia Britannica, Time Life and the BBC.

After screening one film, “something clicked in my mind. Why, I had asked myself, couldn’t these great films be broadcast on television?”

It was an idea that he could never really shake, and several years after graduating he called anchorman Walter Cronkite on a lark for advice on how to make a nonfiction channel possible.

Cronkite not only took the call but also invited Hendricks to New York for a chat. Afterward, Cronkite agreed to make some introductions for the young entrepreneur. One thing led to another, and Hendricks was able to make pitches to the influential investment firm Allen & Co. and later to cable pioneer John C. Malone, who agreed to back the venture. Discovery was a go.

Hendricks thanked both Allen & Co. and Malone, a board member, in a letter to the board announcing his retirement. He wrote that he planned to step down as chairman May 16. (Hendricks had passed on the chief executive reins 10 years earlier, and the company is run by David Zaslav, a former executive at NBC.)

“For over three decades now, I have somewhat envied the legions of documentarians that we have employed who have traveled the world to bring great stories and experiences to our viewers,” Hendricks wrote. “It is now finally time for me to go exploring!”

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