Nguyen Phuc Anh (Gia Long), was the founder of the Nguyen Dynasty and built this tomb for his first wife (Thua Thien) in 1814 after she died. It was finished 4 years later. The tomb was later also used for Gia Long and some other family members. The tomb is also known as Thien Tho Tomb (named after the nearby mountain range).
Gia Long (1762-1820) is somewhat responsible for unifying and naming to what we known as modern Vietnam. He fought and beat the Tay Son rulers that had different parts of Vietnam in their control. After his victories in 1799 and establishing Hue as central capital Nguyen Phuc Anh crowned himself emperor and renamed himself to ‘Gia Long’ which is derived from the words Gia Dinh (Saigon) and Thang Long (Hanoi). Some of his known works include e.g. the Imperial City & the Citadel amongst others.
You can get here by boat, motorbike or car. I can only recommend the motorbike as I have done so. I suggest to take the scenic Minh Mang road out the city and drive parallel to the Perfume River. Cross the QL1A and continue along the same side of the river for about a kilometer until you hit a floating toll bridge and cross it. The floating bridge is an experience on its own. The toll is VND 6.000 for one motorbike including 2 people. Turn left and continue driving parallel to the river for about 3 kilometers until you hit a small intersection with a sign that tells you to turn right to the tomb. A lane of pine trees welcomes you into the complex.
The complex is roamed by a number of guards that speak little English. There are no official tickets available but as far as I can tell the entrance is VND50.000/person and it grants access into all the structures, but I am not convinced it gives access to the actual tombs inside the structures. Suggest to make sure you negotiate the opening of the tombs in the price. We did have an issue the first day with a guard trying to overcharge us on top of his colleague that we already paid for.
Since this area is not too far away from the Bach Ma National Park quite a bit of birds like parakeets, green pigeons, king fishers and others can be seen here at the trees and bush about 100m behind the Geocache. Be careful, there are snakes in the grass.