This temple is just behind the Grand Palace. Its many pagodas have ceramic decorations. Just beautiful.
The main attraction though is the longest reclining Buddha. 46 meters! They surely must have build the temple around it.
The temple complex is one of the six top royal temples and houses the largest collection of Buddha images in Thailand.
On site is also the school of Thai medicine which is attributed to be the birthplace of Thai massage. A museum informs about uses of different spices and herbs as well as anatomical techniques. It also had air condition which drew in even uninterested tourist. You can book a walk-in massage session at the school on site.