As in the days of Vietnam’s emperors, during the last decade or so, West Lake has once again become Hanoi’s most fashionable address, complete with exclusive residential developments, lakeside clubs, spas and a clutch of luxury hotels. A lakeside walk makes a pleasant excursion with one or two sights to aim for. In the seventeenth century, villagers built a causeway across the lake’s southeast corner, creating a small fishing lake now called Truc Bach and ringed with little cafés.