In the Pacific Ocean once has an island called Sandy Island. In 2012 when a group of research reached there found the island missing. The island which is 15 miles long and 3 miles wide. Researcher indeed going down as deep as 4600 meters but found no evidence even a sunken trace.
Since 18 centuries when first eye witness Captain Cook has cleared stated the existence of the island. Even modern satellite has once detected the existence of the island with temperature in this location. It has been on Earth for 230 years and now disappeared. Could it due to geology reasons? Extra terrestrial or perhaps Multi dimensions? Can the island disappeared or re-appeared again?