Phuong Hoang cave and Mo Ga stream is a famous national landscape which still keeps a mysterious natural beauty, which Located at the 42nd kilometre on national highway 1B (linking Thai Nguyen and Lang Son province).

Local old people tell a story about a couple phoenixes finding a place for their net. The couple flew days and nights but were unable to find a place for their net. Hungry and thirty, the birds found a stone trough full of water at the threshold of a cave. They decided to stay in the cave. Time goes by, the male bird got old. It cannot fly for food, it dragged into the cave and died. Its wife came back and did not see the husband, flew to the top of the mountain and waited until its died and turned into a stone. The cave, where the phoenixes lived was named Phuong Hoang from then on. 

The cave and Mo Ga stream are part of a complex of limestone mountains. To reach the cave, visitors have to walk on a zigzagging precipitous path. Tiredness after one hour walking will disappear when they reach the cave, enjoying both its natural beauty and fresh and cool air. Stalactites inside the cave will help visitors imagine their watching an elephant kneeing down, or lions dancing and a woman embracing her child. Looking up, they can see a phoenix spreading its wings to welcome visitors. 

The cave is not only a famous landscape but also a historical relic of the Bac Son-Vo Nhai uprising against the French colonialists. On November 27, 1944, militia and 373 local families with all the weapons they had: flint-locks, scimitars, stone traps and grenades pined a battalion of French soldiers down, causing a severe damage to them.

Going 150 metres farther from the cave gate, visitors will reach Mo Ga stream. This may be a cave-stream with water flowing from the inside. It is unclear how long the cave is. Going about 300 or 400 metres further inside the cave, visitors can see a fascinating beauty of the cave. Stones look like beds of fairies. Visitors can have a great pleasure swimming on a cool stream. Going there, visitors will have chance to taste some local delicious specialty dishes like bamboo-tube rice or wine.

Reaching the mouth of the cave, visitors can see the landscape of this land. The Light Cave is spacious and well-ventilated. The stalactites in the cave glitter fancifully thanks to the light from the three main mouths of the caves. Visitors can freely imagine the forms of these stalactites such as a mother is carrying her son on her back on the way to the field, ancient people are hunting wild animals, and lanterns.