Be in the old town on the night the electricity goes off
A monthly blackout, on purpose
The whole of the ancient town, on the 14th day of each lunar month, from about 8pm.
Why it's unique
This is not a lantern display, which any town can stage. On the eve of each full moon the old town's electric lighting goes off and the streets are lit by silk lanterns and by candles floated on the Hoai River.
The practice was a decision by the local authorities around 1988, and it happens twelve times a year rather than once. A monthly, town-wide, deliberate blackout kept up as civic ritual for nearly forty years is the distinctive part, not the lanterns themselves.
Before you go
The 14th day of the lunar month, not the 15th, and the lights go down around 8pm.
Get onto the south bank or the An Hoi bridge before then. Crossing afterwards is slow, and the bridge is where the view of the floated candles actually is.
Buy your candle a street back from the water. Prices at the bank are several times higher for exactly the same thing.
Shops shut earlier than usual on these nights, so eat first.