Hoan Kiem Lake is arguably Hanoi's public focal point and its surroundings are superb for a game of badminton, jogging or other exercise. Walk over the red bridge and get acquainted with Hoan Kiem Lake's legendary turtle at the 17th century Ngoc Son Temple (you can see its cousin mounted in a glass case).
A legendary tale tells how Emperor Le Loi's magic sword was swiped by a turtle while the ruler was enjoying a day out on the lake. Resigned to the loss of his sword and the disappearance of the crafty turtle, Le Loi concluded that Kim Qui _ The Golden Turtle God _ had reclaimed the sword given to Le Loi earlier when he led a revolt against the Chinese Ming Dynasty. Thus, Le Loi renamed the lake in reference to this event. (Hoan Kiem was formerly known as Luc Thuy _ 'Green Water'.) Today, Hanoi's Hoan Kiem Lake makes for the perfect spot for walking, jogging or shooting photos.
According to VietKings (Kyluc.vn)