The San Andreas Fault, on the Carrizo Plain. Note the stream offsets. This is in Carrizo Plain National Park, which comprises the westernmost of the Southwest deserts in the U.S. To the West, on the left, is the Pacific Plate. To the East, on the right, is the North American Plate. These are two of the largest tectonic plates on Earth. The Pacific plate is eight to nine thousand miles across and weighs 345 quadrillion tons.
The fault is a right-lateral strike-slip fault, which means the other side appears to be moving to the right, no matter which side you stand on. Note how a stream, coming in from the East (right), follows the fault trace for a couple thousand feet before continuing West (left). "Stream offsets" like this one testify to steady rightward movement on the far side of the fault. (Here's a lower-resolution view from above, in Google Maps.)