Waves can cause cliffs to break apart and erode over time. The constant pressure and force of waves against the shore can erode and wear down rock formations, causing cliffs to become weaker and eventually break apart. This process of erosion can create new landforms, such as caves, arches, and stacks, and can also change the shape of the coastline. Over time, the continual erosion caused by waves can result in a retreat of the shoreline, causing the land to slowly sink into the ocean. In summary, waves can have a significant impact on landforms by eroding cliffs and shaping the coastline over time.