Rongorongo and the Indus Valley Script
With its ominous history and its majestic moai statues, Easter Island would be one of the most dramatic places in the world even without an unsolved linguistic mystery. But since it's super greedy when it comes to fascinating stuff, the island is also home to Rongorongo, a glyph language that has yet to be deciphered. Even stranger is Rongorongo's similarity to the Indus Valley script, which was used over 5,000 years ago an enigmatic, West Asian civilization of the same name. The Indus Valley script has also never been cracked, which is especially frustrating given that those peeps founded the largest civilization in the entire ancient world, and among the most sophisticated. Dudes had multi-storey houses with plumbing, while everyone else had mud huts with poop piles. But whatever secrets these languages contain are safely locked in those glyphs for now, right in plain sight. IT HURTS.