A U.S. archaeologist says satellite and drone images have led to a new discovery in the ancient city of Petra — a massive platform hidden under sand.

Traders known as Nabataeans carved Petra into rose-hued sandstone two millennia ago. The UNESCO World Heritage site is Jordan's main tourist draw.

Christopher A. Tuttle of the Council of American Overseas Research said late Friday that the platform was not clearly visible from the ground, and that only images taken from above revealed the shape.

He says only an excavation can reveal its original purpose. He says it may have been used for public displays because it was fronted on one side by columns and a monumental staircase.

Tuttle and a collaborator published their findings in an academic journal last month.