From Phong Nha, I took a boat ride up the Son River. The river flows from Laos and during the wet season, the deep green changes to red; thus the name translated means lipstick.
We reached the mouth of the cave and paddled into another world of stalactites and stalagmites where all was quiet except for the sound of the oars against the current and plops from water drops from the rocks above.
While the river flowed beyond Vietnam’s border, we only floated about a kilometre into the cave.
From here to there 