Once a branch of the Red River, which became a residual lake, Hoan Kiem Lake ("Lake of the Restored Sword") forms the southern boundary of the old commercial town. Its shores were laid out as a public promenade in the 1930s. The shores are now busy throughout the day, but especially in the early hours of the morning, when locals of all ages come here to jog, play badminton or practise Tai Chi. At night, pretty lighting of the lake and the shores.