A short walk from the Dahan Stronghold, Nangan’s [南竿] Beihai [北海] Tunnel is a multi-channeled tunnel 18 meters high, 10 meters wide, and 640 meters long. Soldiers worked for 820 days to complete the project using just blasting powder and hand tools to tunnel through solid granite.
The tunnel’s entrance:
Walking the path takes about 30 minutes to complete and is open to tourists when the tide is out.
In the past, this tunnel was able to accommodate more than 100 small landing craft.
Our guide told us that sometimes fish come in, but the only sea life we saw was a jellyfish.