Ayutthaya was the capital of Thailand from 1350 to 1767, and is a great place to visit on a day trip from Bangkok. We were bussed there and sailed back along the Chao Praya River into the centre of Bangkok. Bang Pa-In on the way is definitely worth a stop too...it's a former Summer Palace of the Royal Family and very impressive. It was most recently restored in 2001 (just after I last visited) and one of the fun things is you can hire a golf buggy to go around the grounds (which are immaculate and very well kept) if the heat is a bit much, but you can certainly walk round, it's not that big! My favourite site in Ayutthaya is Wat Yai Chaimonkorn, where Buddhas line the walls, and are - if memory serves - tombstones for the ashes of wealthy families. Each Buddha is draped in saffron cloth and it's a very striking image. There's also a huge reclining Buddha and the massive stupa is there too...easy to take lots of great photos! Elsewhere there are lots of temples (Wats) which are pretty much all in a bad state of repair. Ayutthaya was ransacked by Burmese invaders, who did things like setting fire to a huge Buddha in Wat Phra Si Sanphet which was covered in solid gold...the fire melted the metal and left a concrete Buddha. The other main site is Wat Thammikarat, where there are many Buddhas still wearing their robes...even though the sites were ransacked by the Burmese they are still considered sacred. But because most of the sites in Ayutthaya are no longer working temples (I think there is one still housing monks) you don't need to worry about covering your legs, etc, but it's still wise to respect local customs. Ayutthaya is a very photogenic and interesting place. It's a shame so much of it go damaged, but it provides contrast to the gilded Wats in Bangkok. I'd say it's definitely a day trip location, and somewhere I'd like to go back to.