Outside the museum, two statues similar to the ones you will find at the Grand Palace welcome you in, and in the lobby is the first of many interactive displays: a skyline of the old town that sends flocks of birds flying as you walk past. Entry to the museum is 100 baht, and you are required to join the two hour tour. This is conducted mainly in Thai, with a special audio headset in English. I recommend sticking close to the guides as you wander around. They speak excellent English and will give you extra descriptions and stories. After a walk down a short corridor that displays a historic timeline, into the first of the nine halls, that displays a 360 degree account of the development of the area.
Read more at: http://www.bangkok.com/magazine/rattanakosin-exhibition-hall.htm?cid=ch:OTH:001