Serindia Plan 34 - Plans of watch towers T xxv, xxviii, and Txxix on ancient Limes north of Tun-huang - Stein did not prepare such plans for every tower, many of which were far too completely ruined. And there are many photos of the better preserved of the towers. Stein always refered to the Han wall as "Limes' reflecting his connection between this and the Roman frontier lines which had a similar strategic purpose.