MICHIGAN CITY, Ind. (AP) — Rangers at the Indiana Dunes National Lakeshore will give guided tours of a popular dune along Lake Michigan closed for nearly two years since an Illinois boy was trapped under sand for more than three hours.

The hikes will use a trail on Mount Baldy that National Park Service officials say has been determined to be safe. The tours will last an hour and will include a high point on the dune that overlooks where the holes have been observed. Other than the tours, the dune near Michigan City remains closed while scientists try to determine what is causing the mysterious holes.

The guided tours will be held on Friday afternoons and Sunday mornings starting June 5 and running through Sept. 6. Reservations are required.