Vinh Yen - or more precisely the area to the north and east of the city - was the site of an important battle in the French-Vietnamese War that preceded ours. Giap - the great Vietnamese general - tried breaking the French forces with a series of concentrated attacks that culminated in a mass charge. He got his butt kicked in the end, but it was a hellacious fight. The outnumbered French used napalm to help hold off the attack. (It was not the first battle where napalm was used, though some people thing so.)
Nobody but the dead and their relatives remember it today.