Lang son in north of Vietnam:
At 150 km from Ha noi, Lang son is a province sharing the border with China.
Lang son is known mainly by military battles during the Indochina War and between Vietnam and China in 1979.
This is especially on the Colonial Road No 4 or RC4 between Lang son and Cao bang travelers will discover a moment of Vietnamese and French history. It is on this road that happened the French military campaign in 1950 to cut the supply path from China People to the Viet minh, a movement for the Independence of Vietnam during the war in French Indochina.