Because Hoi An was relatively umoucued by the American War, it serves as a museum piece of Vietnamese history. More than 800 structures of historical significance have been officially identified in Hoi An, including houses and shops, wells, family chapels for ancestor worship, pagodas, Vietnamese and Chinese temples, bridges, communal buildings, assembly halls of various Chinese congregations, and tombs (Vietnamese, Chinese and Japanese; no original European tombs survive).

Many of Hoi An's older structures exhibit features of traditional architecture rarely seen today. As they have for centuries, some shopfronts (which are open during the day to display their wares) are shuttered at night by the shopkeepers, who insert horizontal planks into grooves that cut into the columns that support the roof. Some of the buildings' roofs are made up of thousands of brick-coloured am and duong (Yin and Vang) roof tiles - so called because of the way the alternating rows of concave and convex tiles fit snugly together. During the rainy season, the lichens and moss that live on the tiles spring to life, turning entire rooftops bright green.

A number of Hoi An's houses have round pieces of wood with an am and duong symbol in the middle surrounded by a spiral design over the doorway. These mat cua (watchful eyes) are supposed to protect the residents of the house from coming to any harm.

Hoi An's historic structures are gradually being restored and there is a sincere effort being made to preserve the unique character of the city. The local government has put some thought into this: old houses must be licensed for restoration work, which must be done in a tasteful manner.

Many of the house owners also charge for the invasion of their privacy - as much as US$3 for a guided tour of the building - but this is negotiable. The government permits this on the basis that the funds will be used for renovation of the homes.