The Great Pyramid of Giza was originally covered in polished white limestone that reflected sunlight like a giant mirror.

The Great Pyramid was constructed using approximately 2.3 million stone blocks, but its most striking feature was the outer layer of Tura limestone. These 'casing stones' were harvested from quarries across the Nile and were meticulously cut to a tolerance of just 0.01 inches. When the pyramid was finished around 2560 BCE, it appeared as a brilliant, seamless white mountain that could be seen for many miles. At the very top sat the pyramidion, a capstone often made of granite and plated with electrum, a natural alloy of gold and silver. This apex would catch the first and last rays of the sun, acting as a literal beacon in the desert. Historical accounts from travelers in antiquity suggest the reflection was so intense that it was difficult to look at directly during midday. The transformation of the pyramid's appearance began after a massive earthquake in 1303 CE loosened many of the casing stones. Bahri Sultan An-Nasir Nasir-ad-Din al-Hasan later harvested these stones to build mosques and fortresses in nearby Cairo. Today, only a few original casing stones remain at the base, providing archaeologists with evidence of the structure's former geometric perfection and reflective brilliance.