While students laid out in the sand and relaxed in the water at the Indiana Dunes beaches, an invisible danger lurked beneath the sand: sinkholes.

Last July, a 6-year-old boy was trapped beneath the sand in July for about three hours.  This sinkhole was the first of many to be discovered on the known dune Mount Baldy.

Following this incident, scientists closed the dune for investigation of sinkholes throughout the entire summer.

According to the National Park Service, two additional holes and several depressions have been discovered, although scientists have yet to find an explanation for their sudden appearance.

Mount Baldy is one of the most visited sites in the national lake shore, attracting thousands of visitors each year according to Acting Superintendent Garry Traynham.  The dune will remain closed until the sinkholes can be resolved and the safety of the public can once again be reassured.

Although Mount Baldy is currently an off-limits attraction of the national lake shore, all other beach areas are open, but it is recommended that the public stay on designated walking paths for safety reasons.