Bimmah Sinkhole.

A striking natural wonder along the coastal route between Muscat and Sur, the Bimmah Sinkhole—locally known as Hawiyat Najm, or "the falling star"—is a massive limestone depression filled with clear, turquoise water. Formed by the collapse of an underground cavern, this 50-meter-wide basin sits just a few hundred meters from the sea, resulting in a unique blend of fresh and salty water that is highly popular for swimming. Visitors can descend a concrete stairway directly into the pool, where tiny fish often nibble at swimmers' feet. Located within a well-maintained, walled public park equipped with restrooms and green spaces, the sinkhole offers an easily accessible, surreal contrast between the arid Omani landscape and the vibrant, deep-blue water below.