Hoan Kiem Lake and Ngoc Son Temple

Hoan Kiem Lake is the centre of Hanoi in every sense. The Old Quarter spreads north of it, and most visitors pass its shores several times a day without planning to. The lake covers about 12 hectares, stretching roughly 700 metres from north to south, and is shallow, with an average depth of about 1.2 metres. Its name means Lake of the Returned Sword.

The name comes from the city's best-known legend. After the Vietnamese defeated the Ming in the 15th century, Emperor Le Loi was boating on the lake when a golden turtle rose from the water and asked for his magic sword, Heaven's Will, which was then returned to the Dragon King who had lent it. The small Turtle Tower, standing on its own island towards the middle of the lake, is tied to the story. The lake was also long home to giant soft-shell turtles; the last known individual was found dead in January 2016.

The main sight on the lake is Ngoc Son Temple, the Temple of the Jade Mountain, which stands on Jade Islet near the northern shore. It dates from the 18th century and honours Tran Hung Dao, the general who led the defeat of the Mongol invasions in the 13th century, together with the scholar Van Xuong and Nguyen Van Sieu, a writer and official who repaired the temple in 1864. You reach it over The Huc Bridge, a wooden bridge painted vermilion whose name is often translated as Perch of the Morning Sunlight. In 1884 a Confucian scholar renovated the site and added parallel sentences and word puzzles to its walls. The temple charges an entrance fee and is open from 7am to 6pm on weekdays and until 10pm at weekends; walking around the lake is free at any time.

The lake is at its best early in the morning, when locals come to exercise and practise tai chi in the gardens along the water's edge. A full circuit on foot takes around half an hour at an easy pace, and you should allow another 30 to 45 minutes for the temple. Crossing the roads around the lake needs care because of the steady traffic, so use the marked crossings and move at a steady pace.

The lake is the natural starting point for exploring the centre on foot. The Old Quarter, with its 36 streets named after the trades once practised on them, begins on its northern side, and St Joseph's Cathedral is a few hundred metres to the west. The Thang Long Water Puppet Theatre is on Dinh Tien Hoang Street, so it is easy to combine a lakeside walk with a show and dinner in the old streets.