Archaeologists in Spain uncovered a previously overlooked tomb while investigating the formation of La Peña de los Enamorados, also known as the sleeping giant.

The Antequera archaeological site in southern Spain is home to a number of ancient structures dating back to the third and fourth millennia BC, including the Menga, Viera, and El Romeral megaliths. According to a study that was published on April 15 in the journal Antiquity, the Antequera site contains both man-made and “natural monuments,” but is best known for its prehistoric megaliths.

The “natural monuments” at the site include La Peña de los Enamorados, a stone “sleeping giant” that towers about 2,900 feet above the ground, researchers said. The Sleeping Giant had a 5000-year-old secret hidden in his chest: Piedras Blancas megalithic grave.