In a mountain valley 15km north of Shānhǎiguān stretches the only section of the Great Wall ever built over water. Normally the Wall stopped at rivers, as they were considered natural defence barriers on their own. At Jiǔménkǒu Great Wall, however, a 100m span supported by nine arches crosses the Jiǔjiāng River, which we can only guess flowed at a much faster and deeper rate than it does today (or else the arches would function more like open gates).
Much effort has gone into restoring this formidable-looking bridge and on both sides the Wall continues its run up the steep, rocky hillsides. Heading left, you can quickly see where the Wall remains unrestored on the opposite side. Sadly, access to this area is blocked but the distant sight of crumbling stone watchtowers truly drives home the terrible isolation that must have been felt by the guardians of frontier regions such as this.
No buses head to this part of the Wall from Shānhǎiguān. A taxi costs around ¥35 one way; ask the drivers gathered outside the South Gate. A return trip will cost more like ¥80 to ¥100, including waiting time.