Indeed. My grandfather used to tell me tales of his day in the Civilian Conservation Corps, building roads in the southern end of the Appalachian Mountains in the 1930s.

They'd be going along clearing out land for a road and they'd come across a hollow with residents who had been isolated for decades, if not a century or more. He said they knew nothing about the world at all, though they would have basic tools from way back. Of course, that was 80 years ago now.

Interesting little story. Did your grandfather say anything about how the people out in the wilderness reacted?

In general they were mistrustful of outsiders and didn't want anything to do with them. Most of them weren't happy about the new roads (these would have been very basic dirt forest-service style roads at the time). They lived in very simple shacks, and of course had no electricity or running water.

Only vaguely related, but after his time in the CCC, my grandfather became a pentacostal preacher, which he remained for the rest of his life. His first "church" was a brush arbor he built himself. Funny how different life was then.

Brush arbor information: http://brusharborquarterly.com/about.html

You might already know about this, but I feel like you might be interested in the people of the North Sentinel Island, some of the "last people to remain virtually untouched by modern civilization": https://en.wikipedia.org/wiki/North_Sentinel_Island

There is also at least one tribe in South America that has never been contacted by the outside world.

http://www.uncontactedtribes.org/brazilfootage

There are a number of tribes along the Amazon who have never been contacted by the outside World, for example Brazil actively tries to identify isolated Indian tribes by fly-over but a policy to not contact them. Here is a story about drug traffickers massacring one of the documented, but uncontacted tribes: http://www.ibtimes.com/uncontacted-amazon-tribe-massacred-pe...

Just to clarify: in Brazil, those "uncontacted" tribes include many (probably a majority) that have had contact with the outside world in the past. However, they currently have no ongoing contact, and the Brazilian authorities don't have enough data about them from the previous attempt at contact.

In some cases, they might have had a less than pleasant experience when they were first contacted by explorers or loggers. Nowadays, while they'd be in danger should they meet illegal loggers and the like, it shouldn't be dangerous for them to contact the authorities. However, their memory from the initial encounter might have been passed on for generations.

Also, as you say, the Brazilian agency in charge of documenting and protecting the Indians has a policy of not forcing contact. So those tribes can remain uncontacted indefinitely.

The page below has more info. Use your favorite translator.

http://mundoestranho.abril.com.br/materia/ainda-existem-trib...

Many of these Brazilian tribes have had some contact with loggers/miners/etc, just no formal government contact.

Perhaps more interesting is the case of the Sentinelese, who live on islands in the bay of bengal, and may have had literally no spoken contact with outsiders in hundreds of years:

https://en.wikipedia.org/wiki/Sentinelese_people

There have been many visits on the shore of their island by Indian anthropologists.

There's a show in France called 'Rendez-vous en terres inconnues' where they get celebrities to "isolated" tribes/groups (polar ring, deep jungle, desert, etc). Paradoxically, often, their lifestyle is not grown out of ignorance or isolation, they chose it. They do interact with our societies, but don't merge. The funniest part to me was how easy it was for them to catch up with us, like using a cellphone quickly became a mundane practical thing for emergencies, nothing was really difficult as far as I could see in the videos. Their children are really drawn to the 'modern' world though. Very sad that they're blinded by shiny things and desensitized to their own treasures.

"Very sad that they're blinded by shiny things and desensitized to their own treasures."

Seems to me this applies for people living in civilization, as they again and again leave it to live as noble savages. Looks a lot like "grass will always be greener on the other side".