Star trails above the Bonneville Salt Flats in Utah almost look like a tunnel into hyperspace. These salt flats are made of approximately 90 percent common table salt, weighing millions of tons. The crust is up to 5 feet thick near the center of this unbelievable landscape that stretches over 46 square miles – just slightly smaller than the size of San Francisco. Photo by Joseph Gruber. Posted on Tumblr by the US Department of the Interior, 5/4/16.