Vietnam has always been a very Buddhist country, so you’ll find a lot of huge Buddhist temples as well as small ones. Southeast Asia’s largest Buddhist temple is located in Bái Đính, Vietnam.
There are thousands upon thousands of Buddhist shrines as well as shrines of native religions spread throughout the country.
The imperial capital of the last monarchy of Vietnam, located in Huế, is largely intact and is for tourism. The imperial capital in Hà Nội however, is littered with French buildings and ruins, so I’m not sure if that’s what you want to see.
Hà Nội does have one of the last historical Temples of Confucius in Vietnam, which is the city’s iconic landmark.
Hà Nội also has the popular French-era Old Quarter that is quite popular with tourists, if that’s what you’re interested in.
Hội An is a well-preserved old town with filled tourists that gives you a look at what a Vietnamese trading port looked like in the 18th century.
Đà Nẵng has Bà Nà Hill, which has a French summer home built during the colonial era. It is also a tourist attraction right now, with its very popular Golden Bridge.
In Hồ Chí Minh City, you can also find Christian remnants as well, with its iconic landmark of the Notre Dame Cathedral.