Hanguangmen

This guide to Hanguangmen in Xi'an puts your hand on a wall that looks like stone but is packed earth, rammed in layers by workers who tamped raw loess into wooden frames to build a gate that guarded Tang dynasty Chang'an's imperial city for over six hundred years. You'll hear how the stratigraphic profile behind the glass records separate building campaigns from the Sui through the Qing, each dynasty patching new earth onto the last rather than tearing the gate down, and how its three passages were divided by rank, with the center lane reserved for the emperor alone. Underneath, engineers solved a harder problem than height: how to drain water through a defensive wall without opening it to intruders.