Being an immigrant from another country (Russia in my case), I have found many things that my culture believes to be obviously true can actually be proven to be false. This particular case, though, is quite puzzling because it appears to have hard physical proofs in Russian, but seems to be shown or proven false in English. I'm talking about quagmires. Actually, the terminology is the first problem, because the Russian word can be variously translated as marsh, swamp, bog, moor, and more. However, the crucial part is a body of fluid that appears solid at first glance, but "sucks" a person (or any sufficiently heavy living being) in. Quagmire or mire seems to be the best translation of this aspect, though I've searched in vain to find any discussion of these online in English. In fact, the words are used figuratively in almost all cases. What tends to be discussed is quicksand. Now, the Russian discussion presented on many websites is as follows (I am not a physicist, so this may be a bit muddled): The mire (or whatever the appropriate term should be) is made up of a non-Newtonian fluid, or, more specifically, a Bingham plastic. It will act as a solid until enough pressure is applied, at which point it acts as a liquid. An inanimate object will not sink as far as it would in water because the buoyant force will turn the liquid back into a solid as soon as it counteracts the weight of the body enough for the pressure to diminish below the level required for the fluid to behave as a liquid. But a human, or other living being, moves continuously, with any movement increasing the downward force, which maintains enough pressure to keep the fluid directly below acting as a liquid, and thus sinking deeper and deeper. In particular, even breathing will require enough movement to sink continuously, though slowly. Assuming the mire is deep enough, it is then impossible to prevent oneself from eventually drowning, absent solid objects within reach to grab on to. The body will then not even float up to the surface, trapped in a now solid mass. So, the only recommendation offered, if the above is not an option, is to move as little as possible, not to take exaggerate breaths, and hope help will reach you before you drown. Now, all sources I could find in English, seem to contradict this notion. While quicksand is stated to be a non-Newtonian fluid, it is stated to be a myth that it is possible for a human to drown in it, due to it being too dense, and therefore more buoyant than water. In fact, the recommendation for someone sinking in a swamp or quicksand, seems to be to lay one's back and float up to the surface as one would in water and, in fact, to breathe deeply to aid oneself in floating up faster! So, is the problem here that quicksand is not the same as a quagmire, which has different physical properties or is one version correct and the other wrong? I should note that sinking without a trace in a mire is not an idea foreign to English culture. "The Hound of the Baskervilles" by Arthur Conan Doyle presents such a scenario, but it is a work of fiction, so I cannot really give it any more credibility than the movies depicting drowning in quicksand, and certainly the physics of the situation are not discussed there.