Many centuries ago, the land of Texas belonged to a tribe known as the Huichol. They were big on cave art, and one of the most startling examples they left behind is what's now known as the White Shaman Rock.
When the Huichol drew the painting - approximately four thousand years ago - they would never have seen a white person before. Why they chose to draw a representation of one, and make it twenty-four feet tall, is, therefore, a complete mystery.