Retaining walls are hard structures used to maintain the bottom surfaces at different elevations. The wall provides lateral support to vertical slopes of soil, which might otherwise collapse. Retaining walls are commonly used to hold soil in place to prevent erosion and flooding, but if you view these structures as just erosion fighters, you are underestimating their usability.
Besides stabilizing a hillside, retaining walls can be used to create more yard space, turn a hill into a multi-level area and even create a raised or sunken patio, garden area, or flowerbeds. To help the aesthetic of your overall design, there are various materials to choose from when creating your structure, such as concrete, stone, wood, etc. Depending on the specific needs of your project, a landscape designer will help you make the most out of your retaining wall, so it suits both your personal taste and outdoor needs.
Poured concrete walls can take nearly any shape and can be used to create a raised garden bed.
If you want a "natural" look, stone is the way to go.
Add emphasis to your yard design with a low maintenance brick wall.
Wood offers flexibility and is good for a subtle appearance.