Egyptian authorities have arrested three people after they appeared in a video selling stones from the 4,500-year-old Giza Pyramids to undercover journalists.

The Interior Ministry announced the arrests Saturday, after journalists from dotmsr, a local website, used a hidden camera to capture horse carriage drivers selling two stones for 250 Egyptian pounds ($32).

One of the men, whose face was blurred in the video, bragged about selling stones to foreign tourists for up to 500 euros.

The pyramids, which were used as sacred burial structures, were built in the fourth Pharaonic dynasty. The Great Pyramid is the oldest and only surviving monument of the seven wonders of the ancient world.