Around 25km north of Dong Van and just a few kilometres from the Chinese border, Lung Cu is a massive flag tower erected in 2010 to mark the northernmost point of Vietnam. The summit is reached by almost 300 steps, and the views across rural villages are stunning. The flag is 54 sq metres, to represent Vietnam's 54 official nationalities.
A return taxi from Dong Van to Lung Cu will cost about 700,000d.