The Dau Go Grotto is found on Driftwood Island, formerly known as Canh Doc Island. The name Driftwood Grotto comes from the popular story of the resistance war against the Nguyen Mong aggressors. In a decisive battle, Tran Hung Dao was given an order to prepare many ironwood stakes to be planted on the riverbed of the Bach Dang River. The remaining wooden pieces were found in the grotto and, as a result, the grotto was given its present name. The entrance is reached via 90 steps up the island. The grotto is divided into three main parts. In the first chamber, many forms can be seen in the rock, depending on the imagination of the observer. In the middle of the chamber, on the top of the pillar, there appears to be a monk draped in a long, dark cloak, with his right hand clasping a cane. Moving into the second chamber, visitors pass through a narrow “door”, naturally formed through erosion. The light here is mysterious, and new images appear in the stone. At the end of the grotto is a well of clear water surrounded by four ancient walls. In this grotto, there remains an engraved stone stele singing the praises of Halong Bay ordered by Emperor Khai Dinh when he came to visit the grotto in 1917.