Bangkok used to be known as the Venice of the east, being so run through with canals (klongs or khlongs in Thai). In the modern city of Bangkok those that remain but are mostly hidden from view, others are filled in or no longer maintained.
However, this is not true of Thonburi which lies on the west side of the Chaopraya river; whilst not exactly a hidden world, it is much less visited by tourists and well worth an afternoon or mornings’ exploration.
You can hire a long tail boat at several of the piers on the east side (Sapan Taksin, Ta Thien, Ta Chang) and then go off for 2 or 3 hours of exploring in Thonburi. The most picturesque klong is Klong Mon starting just behind Wat Arun (Temple of the Dawn), this klong is lined with houses and some small businesses, as well as having some floating vendors – mostly tourist tat. Further in to Thonburi is the Artists House: a canal side residence converted into a craft centre where you can buy prints, paintings and some pottery. In the hundred meters or so after the Artists House, other houses have latched on to the passing trade and made the canal facing rooms into retail with lots of other artefacts are available – garden decorations, mobiles etc. Much of this seems original and unique.
Its hard to say how long this part of Bangkok will retain its charm, there is a lot of development in the area and as the BTS stretches further access will improve. Many old houses along the canal have collapsed and maybe the owners are waiting for a development offer… Better go soon.