Another Garden Design Element Discovered: Horttery

Mystery! Intrigue! What is down there?

Down there is yet another garden design element that I want to find in my garden.

This particular grate at the Dallas Arboretum most likely functions as a place for water to run off the path into an underground network of pipes that take the water off to a nearby lake.

A good solid explanation - functional, rational, simple enough.

Or perhaps it is