sanmenhai scenic area is located in the resurgence of poxin underground river, including sanmenhai karst windows, feilong through cave, shegeng through cave, mawangdong cave, canglongdong cave, dayangdong cave, gantuandong cave, mawangdong degraded tiankeng, shegeng degraded tiankeng, bandong tiankeng, poxin polje, liangwanhe polje and mawangdong natural bridge

      sanmenhai karst windows is opened so far with very convenient access for fengshan-bama road crossing the scenic area. it set up tourist center, several parking, docks, national geopark square and restaurants.

      there are three travelling ways including boat, bus and hiking. boat trip is from the dock beside the national geopark square toward upstream through window i, ii and iii and back to the dock near the resurgence; bus trip is from sanmenhai parking to shegeng through cave and longchan parking, then continue the trail by hiking from mawangdong entrance to feilong through cave, window v, iv, iii, ii and i, back to sanmenhai parking again; the first hiking trail is along the bus trail; the second one is from sanmenhai to nantianmen, through fengcong karst area to bandong tiankeng, heidong cave, lühedong cave and yin-yang hills, to pingwang-jiangzhou road; the third one is from sanmenhai parking toward downstream of poxin river, going through dayangdong through cave in dry season, to liangwan polje and qiaoyin resurgence. most of the geosites have explanation boards and the scenic area has karst excursion guide.

wanshougu cave

   in 1989, andy eavis, the former president of the international union on speleology, coordinated a chinese-foreign cave exploration in sanmenhai area and discovered mawangdong cave, when it was claimed to be the highest cave passage in the world; in 2011 jean bottazzi the famous cave explorer organized an expedition team to do cave diving in sanmenhai, they explored the 5th and the 6th karst windows and found out that they are connected with mawangdong cave; in 2012m jean bottazzi discovered nongcan cave through a blowing hole when making cave investigation, the cave end is separated only 20m by a flowstone wall. they are the same one cave system as a matter of fact.

   this cave is beyond sanmenhai longevity headstream and features large passage and magnificent formations, and it is called washougu, i.e., long long life the cave. washougu cave consists of nongcan cave, nantianmen cave chamber. the northern side passage, and has total length of over 1600 meters: the cave tour starts from nongcan cave entrance, to nantianmen cave chamber via small tunnel, and turns back to the northern passage, and goes out from a small tunnel by the side of shegeng tiankeng, it forms a u-shaped loop tour, taking about 80 minutes.
   because of semi-closed state for long time, nongcan cave features many exquisite formations including helictites and crystal flowers, comparable with that in crystal cave. nantianmen cave chamber
in mawangdong is characterized by 120m high passage, over 3000 square meters chamber, natural bridge inside cave with 70m high, 20m wide-spanning 100m, the largest cave natural bridge discovered so far, it features 450m long the northern side passage and the secret dark circle inside.