The Sentinelese Islanders are one of the last uncontacted tribes of humans left on the planet. These people live their lives just as their ancestors did thousands of years ago, and have no knowledge of the outside world, barring whatever floats onto shore. How the hell can a group of people near a populated area remain uncontacted for so long by outside cultures? We've tried to contact them a few times, sometimes with success, by giving them gifts such as coconuts and plastic buckets, but prolonged contact has still failed to materialize. In addition, the island is geographically unremarkable and has no natural harbors, making it an unlikely prospect for colonization, and the ring of reefs surrounding the island makes landing difficult. Oh yeah, and the tribesmen will often kill anyone who steps foot on their island.
Sentinelese warrior pointing his bow and arrow at a helicopter after the 2004 Tsunami
The Sentinelese are by no means isolated in the general sense of the term, you can almost see the island from the largest city in the Andaman islands, Port Blair. Nor are they the only tribe in the archipelago. Several other tribes still nominally exist, but they have been mowed down by the rapidly rotating mower blade of Western civilization, surviving to this day as drunkards and heroin addicts merely existing in subsidized housing, as is the case among many subjugated peoples, such as the Aboriginals. Sadly, contact with civilization has struck down the great tribes of the Andaman islands with some of the tried and true traditional tools of expansionism: disease, bullets, and alcohol. Tribal traditions that existed for thousands of years are eliminated in a single generation due to abandonment of traditional tribal homes and a general aura of hedonism among the disgruntled youth. It doesn't help that missionaries don't have any qualms over forcing native children into conventional western schools, or whatever rag-tag semblance of a school they can assemble. The result of this is that the next generation finds themselves with little knowledge of their mythology, culture, and even their antiquated way of life.
Imagine the shock of coming from a culture that doesn't have the concept of a number higher than two to modern western civilization. Trees to prefab housing, bows to guns, bugs to canned food, from emphasis on the community to emphasis on the self. It's no wonder that many of these people find themselves lost in the world. The youth must be terminally conflicted; now that they know of the outside world why resign yourself to passive existence as a savage? As has been seen over and over again, great cultures merely whimper out of existence in a ditch, clinging to a bottle of rum.
Luckily, the Indian government has decided that the best policy is to simply leave the sentinelese to their fates, and welcome them if they decide to leave their island home. Here are a couple of links if you're interested in this at all.