It is believed that the Sentinelese first came to the island around 60,000 years ago from Africa. Over the years, people from the outside have tried to visit the island, but each time they have been met by attacks. The Sentinelese do not welcome any kind of contact with the outside world. Because of this, we know little about them. We know nothing about their culture, their language or even how many there are. There could be only 40 or as many as 400.
In 1974, a film crew went to the island to make a documentary. The project came to a quick end, however. Sentinelese warriors attacked their boats with arrows and spears from the beach. One of the film crew was was hit in the leg by a 2.5-meter long arrow. (See the video from the documentary below.) There have been other attempts to visit the island. But they always in a similar way.
The island is under the control of India now and the Indian Navy maintains a 5-kilometer buffer zone around the island, which makes it practically impossible for anyone to get to the island. Currently, the Indian government has no plans to make contact with the islanders, which is probably for the best.