Kanchanaburi

Kanchanaburi (population 52,000) is the gateway to Kanchanaburi Province. For most visitors it holds precisely one sight of interest, namely the Bridge over the River Kwai, the start of the infamous World War II Death Railway to Burma (Myanmar), although there is an increasingly thriving backpacker scene taking advantage of the chilled-out riverside vibe. More foreign visitors are discovering why Thais know it as one of the most beautiful provinces in the country with its easily accessible waterfalls and national parks.
Orienting yourself in Kanchanaburi is very easy. The main road, Thanon Saeng Chuto, runs through the length of town from north to south, connecting the River Kwai Bridge, the train station and the bus station. Running parallel to this, closer to the river, is Thanon Mae Nam Kwae where most of the guesthouses and the local bar scene can be found.

Bridge over the River Kwai
Located some 3 km north of Kanchanaburi (down New Zealand Rd off Saeng Chuto), this iron bridge (Saphan Mae Nam Kwae) across the Kwae Yai river is the main attraction for many visitors. Immortalized in the famous movie and novel, it was a part of the infamous Death Railway to Burma, constructed by POWs working for the Japanese in hellish conditions during World War 2. Some 16,000 POWs and 100,000 Asian workers died during the railway construction. The present iron bridge is the second wartime incarnation (a part of the original can be found in the War Museum), but 2 central 'boxy' spans were rebuilt after the war to replace three sections destroyed by Allied bombing.
You can cross the bridge on foot. While the center of the track has been thoughtfully turned into a steel-plated walkway and there are little side platforms between the spans for sightseeing and avoiding trains, there are no guardrails so vertigo sufferers and small children should steer clear. Off the end of the bridge, you can feed or ride an elephant bare-back at negotiated price of 600 baht per ride.
The State Railway of Thailand operates a little tourist train with which you can drive across the bridge and back again, at 20 baht for the 15 minute round trip.
Art Gallery and War Museum

This well-signposted complex is located about 50 metres from the bridge and houses a bizarre collection of museums and exhibits, most of which are poorly maintained and labeled. Open 08:30-16:30 daily; admission to the whole lot is 30 baht.
War Museum. To your left as you enter is this four-story building encrusted with statues, which starts off with a little Burmese shrine but is mostly devoted to pre-WW2 Thai history through the ages and is filled with wall paintings of kings and racks of rusty pistols. There are good views of the bridge from the roof of the riverside building.
World War II and (old) JEATH Museum. Lurking in the basement, this is the main drawcard and features a section of the first wooden bridge, recreations of the POW barracks and random military paraphernalia. Downstairs is an exibit of prehistoric Thailand complete with semi-erotic murals.
Jewelry Museum. Above the WW2 museum is the most bizarre section, housing (among other things) dusty stamp collections and a gallery with wall paintings of all Miss Thailand winners.