(CNN) - Egypt is investigating a video showing a couple posing nude at the summit of the Great Khufu Pyramid of Giza.
The video was posted Wednesday on YouTube by a Danish photographer named Andreas Hvid. He's known to post images on social media from high vantage points around the world, sometimes featuring nudity.
Hvid says he's always dreamed of climbing that pyramid and contacted friends from Denmark to do the stunt last month.
Egyptian authorities say they want to know how the couple avoided security and managed to scale the pyramid.
Under Egyptian law, it’s illegal to climb pyramids.
Hvid has said he will not return to Egypt in the future.