Hanoi is surrounded by lakes and has its own history. The most beautiful lake is Thuy Lake, renamed Hoan Kiem (The Lake of the Returned Sword).
According to the legend of the Lake of the Returned Sword, in 400, Vietnam is invaded by Chinese enemies. At that time, the country was led by King Le Thai To (Le Loi). The Chinese won many battles but one day, Le Loi found and collected a very special sword because it was given to him by the Golden Turtle God (Kim Qui). From that moment on, Le Loi became invincible, defeated the Chinese Ming Dynasty and finally obtained the independence of Vietnam from the Chinese Empire.
After the war, Le Thai To resumed his normal life but he often went to Lake Luc Thuy to practice with his sword. One day, a giant turtle emerged from the waters and asked him to return the magic sword. The king Le Thai To obeyed and the sword, floating in the air, went towards the turtle. With the sword in his mouth, the turtle dove back into the lake. Since then the lake has been called "Hoan Kiem" ("lake of the returned sword").
According to local folklore, the appearance of the giant tortoise of the lake of Hanoi occurs only on special occasions or for an extraordinary event. Even today, it is said that someone occasionally sees the turtle emerge from the lake and this would bring a lot of luck. Having a curved shell above, like the sky, and square below, like the earth, the turtle depicts the entire cosmos.
Moreover, in Vietnam, the turtle is not only the symbol of longevity and immortality, but also the symbol of transmitting spiritual values in Vietnamese tradition.