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.
DIY - Homemade Gabion wall ie rocks encased in wire baskets and used as a retaining wall - creates a dramatic feature in a garden. No directions on link. Nice someone figured out how to landscape with river rock. I swear they grow!
at Sea Ranch - Ramirez and his partner, Sarah Mason Williams, dine at a sequoia table by Redwood Burl next to a hulking juniper tree that they asked the architects to preserve as a centerpiece of the property. Photo by: Mark Mahaney