Easter Island, or Rapa Nui as it is called locally, is a fairly small island five hours from the Chilean mainland with Polynesian roots and which is part of Chile. It is best known for its giant stone heads (moai) erected on a series of stone platforms (ahu) around the island, which are often visited by tourists. The exact meaning of the heads is unknown, but it is assumed that they were erected for religious and cultural purposes. They were later all knocked down both by forces of nature (a tsunami) and by the Rapa Nui themselves. In more recent times they have been erected in several key places on the island, such as Tongariki (where you can watch the dawn) and at Anakena beach. Many more are still waiting, half-unearthed at the Rano Raraku quarry.
Competing theories about the origin of the Rapa Nui people persisted into recent times, but it is now definitively known that the Rapa Nui are originally Polynesian, and there is traditional dance (both modern and traditional) and music, but you're most likely to come across it prepared for tourists. You can also hike, bike, snorkel, scuba dive, go horseback riding, fishing or surfing while on the island in addition to visiting the various sites of archaeological importance.