Vietnam is a very beautiful city, very nice and friendly people. You will find lovely scenery and food. There are many things to explore in Vietnam, In short, I would like to tell about places which I have experienced and would like to recommend you same.
The Sand Dunes of Mui Ne
It is worth place to visit if you have not seen dunes before. Try visiting in the noon, if you visit there in sunrise or sunset you will find a lot of tourists around which leads to a crowded place and will not able to enjoy the beauty of sand dunes. It will be quite hot and can be chances of getting tan; you must take sun tanning cream with you.
Phong Nha Caves
I will definitely recommend you to visit Phong Nha Caves. It will be nice experience visiting there. Great combination of a river with caves as the river runs right through the caves, you will get a beautiful glimpse.
Cu Chi Tunnels
It is underground tunnels; I never had experience with these kinds of tunnels though it was my first exposure. You will dig into past and will know about secrets of these tunnels and war of Vietnam. The guides were fluent in English and safety was their top priority.
My stay was at Oriental Central Hotel. They will treat you like royals, services and staffs were really good and helpful. You will have a nice vision of the city and to walk around.
You may also visit Luang Prabang
Luang Prabang is known for the ancient magnificent Buddhist temples with beautiful, colorful architecture work. You will get to know about Buddhist religion and will feel good vibes.
In Luang Prabang you can stay at Namkhan Eco Farm, It is very beautiful place surrounded by nature. It is a farm and you will get tempting farm fresh delicious food there. There you will get to interact with locals and people all around the world. You will definitely get exposure to their culture and living.