Thang Long Water Puppet Theatre is the best-known venue in the country for roi nuoc, Vietnam's traditional water puppet art. The theatre at 57B Dinh Tien Hoang, on the northern edge of Hoan Kiem Lake, puts on multiple shows daily; seats are tiered around a pool stage backed by a traditional pagoda facade. The performers are hidden behind the facade, controlling the puppets through the water via bamboo rods and hidden string mechanisms that have been kept family secrets for generations.
A typical performance runs about an hour and covers a set of traditional vignettes: farmers planting rice, the restored sword legend of Emperor Le Loi, dragons spouting water, frogs chasing fish. A live orchestra accompanies each scene. You don't need Vietnamese to follow it — the stories are pantomime, broad and clear. Book tickets in advance; the theatre sells out regularly, especially in the evening. Sit toward the back of the raised seating if you can — the view of the whole pool is better than from the front rows.