Ba Be Lake is one of the 16 most bueautiful lakes in the world, lies in the middle of the vast limestone mountain range of Ba Be National Park. With large and small islands of limestone rising out of the water, many of which can be explored as you kayak around them. There are also several caves to find, with beautiful rock formations that have developed over millions of years. A good example is Puong Cave, through which the Nang river runs. It is 30 metres wide, and 300 metres deep with thousands of stalactite and stalagmite structures and a bat colony numbering tens of thousands. Its picturesque entrance lies to the north east of Ba Be Lake, in the hillside of the Lung Nham Range.