Egyptian tour guide sparks outrage after drawing with chalk on 4,000-year-old pyramid An Egyptian tour guide has sparked widespread outrage and calls for a formal investigation after a video of him using chalk to draw on the walls of an ancient pyramid went viral. The footage shows the guide being confronted after marking the exterior walls of the 4,000-year-old Unas pyramid. Experts warn that chalk contains chemicals that could react with the ancient stone, potentially damaging the structure or