The Thien Mu Pagoda is a stunning temple, perfect for spending a couple of hours. Its pagoda is seven stories high and the largest religious building in Vietnam. The Thine Mu Pagoda is regarded as the unofficial symbol of the former imperial capital.
You need around 30min to walk through the temple and its beautiful garden. But plan in some extra time. There are many quiet and peaceful spots in there where you might just want to take a break, sit down and take in the view and ambience. When I visited the pagoda, the monks were playing soccer in the backyard, so the rest of the place was quite empty and super quiet.