The Ban Gioc waterfalls are 1/2 in Vietnam and 1/2 in China. They are the highlight of most peoples visit to Cao Bang. Though you can easily make a round trip from Cao Bang city… 

Angel Eye mountain is a really special spot fairly close to Cao Bang city. There are homestays close by and even a camping operation that you can book online (though if you message them directly… 

Phong Nam is an amazing valley with a winding river and limestone Karst mountains. Foreigners are required to get a special permit to stay overnight. These are easily sourced, same day, in Cao Bang city.… 

An under appreciated mountainous province in the northeast. Some of the most pastoral views can be found in the countryside. Many come to Cao Bang, go to the Ban Gioc falls, then leave. A night…