Its a nice place
This temple is on an island in the middle of Hoan Kiem Lake. It's a nice spot to relax but you can also find the embalmed remains of a gigantic turtle, who was fished out of the lake in 2011. The temple dates back to the 18th century and is pretty small, but again a nice place to visit.
Marooned in the middle of Hoan Kiem Lake is this unassuming quiet temple. It's none of the most visited temples in the whole of Vietnam, so expect to be fighting for elbow room a little. However, if you're lucky and the crowds aren't there, it's a great place to sit and reflect on life for a while. It's also a place which locals come to give offerings to the gods including burning fake money. The temple is connected to the mainland by an attractive bridge which is worth an instagram shot for sure.
Pretty and worth roaming around mainly to get off the busy streets
The Ngoc Son Temple sits on Jade Island in Hanoi's Hoan Kiem Lake. Due to its central location in the middle of the city's Old Quarter and the picturesque Huc Bridge you must cross to reach it, the temple is always crowded. Very crowded. Go early to avoid the crowd. Or just enjoy from across the water.
This pretty temple is situated out on the middle of Hoan Kiem Lake in the old town and you cross a beautiful bridge to access it. The temple was formerly used as a country villa throughout the 16th and 18th centuries, before becoming a Buddhist pagoda in the 19th century. Finally, it was turned into a temple for a Chinese warrior. These days, it's dedicated to a 13th century Vietnamese military national hero.