Archeologists have discovered a monument “hiding in plain sight” in the ancient city of Petra, Jordan. The monument is about the length of an Olympic-size swimming and twice as wide, according to a study published in the Bulleting of the American Schools of Oriental Research.

The monument, a large platform, was found using drone photography and satellite images.

The new discovery is unlike anything found before in Petra, mostly known for its monasteries carved in sandstone. According to National Geographic, the structure consists of a platform that encloses a smaller platform. The interior platform had been lined with a row of columns.

The platform, approached by a monumental façade, most likely had a public, ceremonial function. It has yet to been excavated, but archaeologist Christopher Tuttle suggested the new discovery may be a remain of Petra’s early years, dating back to the fourth century BC.

Tuttle told National Geographic that someone must have stumbled upon the platform before.

"I'm sure that over the course of two centuries of research (in Petra), someone had to know (this site) was there, but it's never been systematically studied or written up," he said.

"I've worked in Petra for 20 years, and I knew that something was there, but it's certainly legitimate to call this a discovery."