A mandatory helmet law came into force in Vietnam in December 2007. Helmet use went from about 10% to about 99% overnight. Everybody wears helmets now, only in the countryside you occasionally see some people riding with no helmet.
On Good Friday, I checked into a hotel in My Tho. This is part of the Mekong Delta region of Vietnam. The Mekong goes through Vietnam, Cambodia and Laos but in the delta it splits into loads of smaller rivers which lead to the coast. Here you can see a view from the hotel room, looking down on a market with the river in the background.