Nature

3. A low area of land between hills or mountains, often with a river running through it.
5. The boundary between land and sea, including cliffs, beaches, and other features.
7. A large, flowing body of water that usually empties into an ocean, lake, or sea.
8. A natural underground hollow or passage, especially one with an opening to the surface.
12. A sandy or pebbly shore beside a body of water, often visited for recreation.
13. A place where water flows over a vertical drop or a series of drops in a stream or river.
15. A large landform that rises steeply above its surroundings, with a peak or summit.

1. A dry, barren area of land with little or no vegetation, often sandy or rocky.
2. A large mass of ice moving slowly over land, formed from compacted snow.
4. A large body of water surrounded by land, usually freshwater and larger than a pond.
6. A large area covered chiefly with trees and undergrowth, often home to wildlife.
9. A mountain or hill with a vent or crater through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.
10. A deep gorge, typically with a river flowing through it, formed by erosion.
11. A piece of land surrounded by water, smaller than a continent and larger than a rock.
14. A wetland area dominated by grasses, rushes, and other herbaceous plants.