The tower here sits on an island in Hồ Hoàn Kiếm, a lake just south of the old downtown. Hồ Hoàn Kiếm: means "Lake of the Restored Sword", and there's a story behind that.
In 1427, Emperor Lê Lợi fought off the Ming occupation of Vietnam with the help of a sword called Heaven's Will, which had been found in the sea. According to legend, a giant turtle emerged from a lake after his victory and asked him to return his sword to its rightful owner: the Dragon King, who lived beneath the water. So, Lê Lợi drew his sword out of its scabbard and threw it to the turtle, who snatched it from the air with its teeth and descended back into the lake. For long after that, a flickering light was said to be seen from the murky depths.
The lake had been called Green Water Lake, but Lê Lợi named it Lake of the Restored Sword, and the tower in its midst is called Turtle Tower.
Here is a bridge across Hồ Hoàn Kiếm:
© 2011 John Baez
baez@math.removethis.ucr.andthis.edu