Historian Andrew Carroll searches for the 'Great Forgotten History' of America and Los Angeles (Map)

Some of the first experiments to invent television happened in a Hollywood apartment, though neither the people living there, nor the neighbors, had any idea until historian Andrew Carroll knocked on their door.

He’s a New York Times bestselling author who found the apartment – and other little-known places in L.A. – while working on his new book "Here Is Where: Discovering America's Great Forgotten History."

He has been called America’s "Indiana Jones," a title Carroll laughs off. He certainly doesn’t crack a bullwhip or wear a fedora.

His main tools are a Hertz rental car and a cell phone. He wears glasses and a button down shirt.

The Washington DC-based historian crisscrossed the U.S. several times for the book, traveling to all 50 states and collecting enough research to fill two-dozen file cabinets.

“It became like a scavenger hunt, to go around the country looking for these places and confirming that they’d escaped notice somehow,” said Carroll.

Among the discoveries:

• A small town in Oregon where the oldest human DNA in America was found.
• A lab in Iowa where the first U.S. car was invented in 1890.
• An Idaho farm where a 14-year-old boy got the inspiration for TV.

Philo Farnsworth's Hollywood apartment

It was that last finding that led Carroll to Hollywood.

“It was in this modest two-story apartment building that a young Philo Farnsworth came with his wife in May 1926, and it it’s in this first floor apartment where he did the first inventions to create television,” Carroll said, standing outside the light blue building on a recent afternoon.

Farnsworth fits with the theme of Carroll’s book, because the inventor has long been largely anonymous. (Though he was honored posthumously at the 2002 Emmy awards.)

The only time he appeared on the medium he helped invent was in 1957, when he went on the game show I Have a Secret.

The contestants had to guess Farnsworth’s identity, but they all failed, miserably. View a portion of the episode below:

The lab where Farnsworth later demonstrated his TV in San Francisco is marked, but few people know about the apartment in Hollywood where he conducted experiments, least of which those living there now.

That was until Carroll recently appeared on their doorstep.

“I’m always afraid I’ll be shooed away as a crackpot," said Carroll. "It is a little strange to knock on someone’s door and say: ‘Hey I’m a historian and something happened here.’”

The reaction he gets often depends on the neighborhood. Those in more upscale areas tend to be less thrilled about a plaque going up, and possibly attracting tourists.

Eric Ando Terharutunyan, who lives next to the apartment where Farnsworth once lived, couldn’t be more thrilled.

“TV was invented in your house!” Terharutunyan yelled to his neighbor. "It just looks like an ordinary house."

Carroll wants people to wonder: 'What else is out there?'

Saying this was the place where TV was invented is probably a stretch. There were other people who contributed in other places.

Indeed, many of Carroll’s “forgotten” places were probably forgotten for a reason. Calling them footnotes to history? Generous. But for Carroll, no monument is too insignificant. His goal is to get people excited about the past, to realize it’s not just something you go see in museums.

“It changes the world around us,” Carroll said. “It makes you wonder ‘What else is out there?”’

Carroll says his obsession with history is somewhat ironic, because growing up he had little interest in it. That changed with a terrible event while he was in college.

“Our house burned down in Washington D.C., and everything was destroyed,” said Carroll. “It was really losing all of our family memorabilia that got me interested in the past.”

'Forgotten' sites for actress Hedy Lamarr and pilot Francis Gary Powers

Carroll recently found a house in the L.A. region where the actress Hedy Lamarr and the composer George Antheil performed experiments that laid the groundwork for another crucial technology: spread spectrum communication.

“Our use of Wi-Fi, cell phones, and Bluetooth is in many ways thanks to what Hedy Lamarr invented many years ago,” explained Carroll.

In Burbank, Carroll found the baseball field where pilot Francis Gary Powers crash landed his KNBC helicopter in 1977. Powers is famous for surviving another crash in 1960, when his U2 spy plane was shot down over Russia.

“It’s just sad that this man survived a U2 crash that became such a big incident (and) died in a helicopter crash here in Los Angeles,” said Carroll.

While the historian continues to search for more “forgotten places,” he’s assembling a massive collection of more than 90,000 wartime letters in Orange County.

They will be accessible to students at Chapman University starting in November.

Below is a map showing some locations identified as "Lost Sites." Do you have a suggestion to add to the map? Tell us in the comments below or tweet @kpcc with the hashtag #LostSites.

• 1: The location Philo Farnsworth conducted experiments that led to the creation of television.
• 2: The location near the Sepulveda Dam Recreational Area where Francis Gary Powers died in a 1977 helicopter crash.

(Locations are approximate)