Walls can be built in several different styles, and with many different types of material. Check out the pictures below to see some walls we've built.
Willamette Graystone: www.willamettegraystone.com/retaining_walls.php
Mutual Materials: www.mutualmaterials.com/product-categories/hardscape/retaining-walls-2/
Empire Stone: www.empirestoneco.com
Cement Product: www.cementproductsmfg.com/?cpmpp-filter=1&cpmpp-product_type-11=retaining-walls