Cot Co, the ancient 59m "Flag Tower"
Sightseeing in Hanoi picture - next to the Army Museum is the tallest point in Hanoi. The tower, once part of the Hanoi Citadel, was built by the French as an observation tower in 1812, and is one of the few old architectural gems to survive the French and American wars in Vietnam. Apparently, the tower has the best view of central Hanoi.