Put simply, a bong is a kind of filtration device - much like a hookah - that is used for smoking tobacco or herbs. Over time, and especially in the last century, the bong has seen an incredible amount of adaptions vastly setting it apart from it's humble beginnings. What started out as a way for early civilizations to smoke their plant of choice with some added smoothness has become so much more. Many bongs - also known as "water pipes" - look more like pieces of art than simple tools.
Modern water pipes come in a seemingly endless variety
I should say this early on: there is no conclusive evidence to say which part of the world the bong originated in. In fact there was some kind of smoking device in the large majority of ancient civilizations because, hey, our ancestors liked to relax too.
The oldest "bong-like" remnants attributed with cannabis use were found in Africa by J.C. Dombrowski - and were found to have cannabis residue when tested. These pipes were cleverly crafted - lighted coals were placed in a bottle buried in the ground, while hemp was placed on top of the coals. The smoke reached the mouth tube through an underground duct that was some distance away from where the pipe lay below the ground.
Additionally, according to historical evidence, cannabis smoking in Africa preceded the smoking of tobacco. A research article by John Edward Phillips reads "The most likely hypothesis is that cannabis was smoked in water pipes in eastern and southern Africa before the introduction of tobacco. "
Similar earth pipes have also been found in Central Asia, though there is a vast distance between the two continents. Besides the earth pipe, many variations of pipes were also used by people in Arabia, Asia and also Africa to smoke both tobacco and cannabis. Water pipes were used in China for smoking tobacco, one notable example being the Dowager Empress Cixi who went so far as to be buried with three exquisitely crafted water pipes. These pipes are on display in the Palace Museum in China.
Three of the water pipes originally buried with Empress Cixi
As far as the actual word "bong", the common theory is that it comes from the Thai word baung - which is used to denote a wooden pipe made from bamboo. There may be one other possibility, however. Located in modern day Kenya is a quickly disappearing tribe called the Bong'om. Perhaps the Thai took the word from the Africans and not the other way around? It's unfortunately impossible to know for sure.
Today's bongs are nearly unrecognizable when compared to their ancient counter-parts. Advances in technology have allowed for the creation of bongs previously impossible, while being made with materials previously unknown - such as the popular borosilicate glass you see in most high quality scientific glass water pipes.