Yellowstone became the world's first National Park in 1872. Today it remains as one of the only large areas in the lower 48 states free of settlements, farms, fences and other developments. Yellowstone is a place of wonder and incredible beauty. Travertine Terraces are seen at Mammoth Hot Springs in the northwest corner of Yellowstone National Park. Travertine is a form of calcium carbonate that is dissolved from limestone beneath the ground and then carried to the surface by hot water. The colours represent a variety of bacterial algae that survive at various water temperatures.