When originally built, what was the outer layer of the Great Pyramids covered in? Is #1 able to withstand erosion over time?
Egyptian pyramids
When originally built, the Great Pyramids had a thin surface of limestone covering the bricks, making them shine in the sun. Over the centuries, the limestone layer has been removed by thieves and erosion, exposing the more common stone bricks underneath.
Ancient pyramid-shaped masonry structures located in Egypt
Do the Egyptian pyramids look the same from outside as they did when new?