I came to shoot the white sand dune (not showing on the right of the frame), this is what Bau Trang (Phan Thiet, Vietnam) is well known for.
Unfortunately, it was cloudy and so there was no hard sunlight to cast shadows on the sand.
Instead, I aimed for a blue boat spotted on the shore of the grassy lake and shot at the moment the sun just lit up enough to make the sand hill in the background glowed.
A Circular Polarizer filter was used to cut down the reflection on the water, thus revealed the bottom of the lake.
This means... I'll be back another time for the sand dune.