Parks Past, Present, and Future Activity Source: Adapted with permission by National Park Service. Over Earth’s 4.5 billion-year history, tectonic upheavals and colliding plates formed mountain ranges and carved out basins. Forces of erosion and weathering have been at work to break down these landforms. Records of these processes are imprinted on the land and define distinctive landscapes around the United States and in its national parks. The dynamic processes that formed the spectacular landscapes of many national parks remain active today. [Read More]