Wat Arun, known as the Temple of Dawn, is located across the Chao Phraya River from Wat Pho. It is the tallest temple in Bangkok, and visitors can climb to the top of the very high central tower for 50 baht, about $1.65 USD.
You’ll have to take a ferry to get to Maharaj Pier and then another to cross the river. The cost? 15 baht to the first pier, a whole 3 baht to the Wat Arun pier. Not bad at all, but it is a bit time consuming waiting for boats to come in.