Living wall is a great alternative to cement block retaining wall - and if done well, it can be the focal point of a garden as well.

The Natural History Museum in Los Angeles, California, has transformed its asphalt parking lot and reclaimed the three-and-a-half acre land as a nature's garden. The green space includes a walkway where visitors can take a leisurely stroll and admire the plants and wildlife - a particularly rare treat in the urban environment of Los Angeles.

Bordering the walkway is the museum's Living Wall, which is constructed from vertical spears of stones that are installed vertically - at a slightly random and haphazard angles - leaving cracks between the individual shards for spaces to plant succulents and other plants. The wall is made from 3.2 million pounds of Pritchard Flagstone, a colorful sedimentary rock with bluish gray, tan, and rusty colors.