The AB Aztec Collection is inspired by the walls in Cusco, Peru, Capital of the Incans which are more than 500 years old. The AB Aztec Collection is easy to install. These blocks dry-stack without mortar or footings. The hollow core feature makes them easier to handle and promotes good drainage behind the wall. The raised lip and notch lock each block in place and creates a natural setback. Use one block size or mix the different block sizes together in the wall to create a beautiful pattern. The AB Aztec Collection is right at home in residential settings where retaining walls 6ft (1.8 m) and under are typically called for, and up to the task on larger retaining walls 6ft (1.8 m) and over.

https://www.allanblock.com/products/aztec-collection.aspx