Gabion walls don't need any kind of drains because they are porous throughout. Gabions can be customized to make them more useful in public spaces. Gabions can be filled with any heavy material--diverse stones, metal artifacts, obtanium, etc.
The best DIY projects & DIY ideas and tutorials: sewing, paper craft, DIY. Diy Crafts Ideas This would be neat to mount on the side of a out-building and plant with herbs and lettuce, freeing up garden space for veggies.