The park is built in the shape of Thailand and houses 116 replicas, reconstructed monuments and architectural attractions. Each of the structures are placed in it's geographically correct position within the Thailand-shaped park. Some of the monuments are life-sized, while others are scaled down. Spending a day here will give you a great tour of the history of Thailand and you can even opt for a private guided tour in English, though of course at an extra cost (1500 Baht).
The architecture on display throughout the park is absolutely amazing, a lot of it quite difficult to find nowadays throughout Thailand. Apart from some major reproductions such as the floating market, the reclining Buddha, the Pavilion of the Enlightened and the Giant Swing and Brahmin Temple, you can also see and walk through realistic depictions of traditional Thai villages which are still in abundance today in rural Thailand, but unless you have Thai friends or relatives to take you, it would be difficult to see during your stay.
Ancient Siam really is very beautiful and it is so large that you can spend a peaceful day roaming or cycling and only run into someone every now and then. Bicycles, and even 2 and 3 seater bicycles, can be rented inside the park for 50 Baht each (100 and 150 Baht respectively for duo and triple bicycles).
The park is roughly 15 kilometers from the airport and is accessible in 40 minutes. Admission is 300 Baht for adults and 150 Baht for children. It is open