It's not exactly sunken treasure, but it's just as mysterious: A grand piano has appeared on a sandbar off the Miami coast. Weighing in at 650 pounds (or more), it sits at the highest spot along the sandbar, which keeps it from being submerged during high tide, reports the Miami Herald. Authorities aren't sure how it got there—and they have no plans to move it. "Even a car can become a habitat for wildlife," says a Florida Fish and Wildlife Conservation Commission rep. "Unless the item becomes a navigational hazard, the Coast Guard would not get involved.'' (More piano stories.)