Here's a geographical mystery for you. An island in the middle of the Gulf of Mexico has gone missing, and nobody has been able to figure out what happened to it.
The island of Bermeja appeared on maps from the 1500s to the 1700s, a tiny dot of land lying roughly 55 nautical miles (102 kilometers) off the northwest coast of the Yucatan Peninsula. It was too small to be of much interest to anybody until the 2000s, when the U.S. and Mexican governments both began to covet rich oil deposits in the Gulf of Mexico. Mexican legislators spotted the tiny island on some old maps, and realized that its presence would extend Mexico's territorial limits and give the country a claim to more of the oil.
The problem, though, was that when researchers from the National Autonomous University of Mexico started looking for the island from the air, they couldn't find it. Studies with underwater sensing devices couldn't locate a submerged land mass in that area, either. They concluded that contrary to the old maps, the island didn't actually exist.
Not everyone, though, was willing to accept the notion that old-time cartographers had simply made a mistake. A conspiracy theory took hold that the U.S. secretly had bombed the island and blown it to bits, in order to solidify its claim to the oil. However, Julio Zamora, president of Mexico's Society of Geography, told Lonely Planet it was common for mapmakers in the 16th and 17th centuries to create maps with errors so enemy countries would not use them [sources: Stevenson, Wilson].