Legend claims in the mid-15th century Heaven sent Emperor Ly Thai To a magical sword, which he used to drive the Chinese from Vietnam.
After the war a giant golden turtle grabbed the sword and disappeared into the depths of this lake to restore the sword to its divine owners, inspiring the name Ho Hoan Kiem (Lake of the Restored Sword).
The area is best Fridays to Sundays when nearby traffic is banned 7pm to midnight and a public-square, fun-fair vibe takes over.
Every morning at around 6am local residents practice t’ai chi on the shore. The ramshackle Thap Rua, on an islet near the southern end, is topped with a red star and is often used as an emblem of Hanoi.