Gabion walls are galvanized steel baskets filled with rocks. They can differ in size and shape and you can add them anywhere you want. For instance, you can place them as fence in your yard to add more privacy over there and at the same enrich the landscape.
And guess what? There is nothing difficult in making one such wall, and you can even do it on your own. You can also use such walls for fire pits, benches or other furniture pieces, garden edging etc. Here are several useful tutorials that you can use as a guide.
Gabion Wall Tutorials
Find some examples of already finished gabion walls that beautify the outdoor space.