The Egyptian pyramids, particularly the famous ones at Giza, are not a single color but rather a mixture of colors that have changed over time. Originally, they were covered in smooth, white Tura limestone which reflected the sun and gave them a bright, glowing appearance.
Over the centuries, much of this outer casing has eroded or been removed, exposing the underlying core of rougher limestone which is a duller beige or tan color. The pyramids can also appear different colors at various times of the day, depending on the angle of the sunlight and atmospheric conditions, ranging from light cream to a deeper shade of yellowish-brown.
In conclusion, while the original color of the pyramids was a bright white due to the limestone casing, what we see today is a result of natural weathering and the passage of time, revealing more muted tones of beige and tan.