Wat Arun, locally known as Wat Chaeng, is situated on the west (Thonburi) bank of the Chao Phraya River. It is easily one of the most stunning temples in Bangkok, not only because of its riverside location, but also because the design is very different to the other temples you can visit in Bangkok. Wat Arun (or temple of the dawn) is partly made up of colourfully decorated spires and stands majestically over the water. Wat Arun is almost directly opposite Wat Pho, so it is very easy to get to. From Sapphan Taksin boat pier you can take a river boat that stops at pier 8. From here a small shuttle boat takes you from one side of the river to the other for only 3 baht. Entry to the temple is 100 baht. The temple is open daily from 08:30 to 17:30.
Read more at: http://www.bangkok.com/attraction-temple/wat-arun.htm?cid=ch:OTH:001