An old friend of mine who loves midevil history told me one time about a 13th century landmine used in northern and eastern europe. It consisted of a hole in the ground, a ceramic container filled with oil, wax chunks, lots of animal fat, and wool (like cotton balls?), sealed with tar (how do you do that without igniting the contents?) and a lid with a 1-2" diameter shaft (pipe, tube) in its approximate center. Inside the shaft was stuffed tightly with densely packed wood shavings, dried moss, other dried nature products, and all soaked in oil. Above this was another pot filled with water, also sealed shut with tar. In the bottom of the pit a very wide clay plate was placed, on top of which were many red hot coals. The oil/wool/fat/wax chunk-filled pot was placed ontop of the hot coals. The mine layer would then ignite the top of the tube filled with wood shavings until it burned hot, then he would blow it out, causing it to smolder. Then the water filled pot was stacked ontop of the other pot. The rest of the hole was carefully filled with loosely packed green leaves and branches, then the hole was disguised by laying branches over it and covering the faux platform with surrounding fauna. For upto 5 days the coals smoldered hot and caused pressure to build up inside the lowest oil-filled pot. The wax and animal fat inside melted and mixed with the oil because of the wool. This mixture became superheated, and stayed sealed because the weight of the water pressing down on the fragile pot lid kept it shut, despite the tar melting eventually. If a poor soul on a horse, or a heavily armored warrior trudged over the device, his weight would crack the weak top bowl of water, causing it to splash down onto the lower pot. the thermal shock of water on very brittle, hot ceramic caused the lower pot to shatter, releasing the super-hot flammable mixture at high pressure. the water also causes the fat and wax/oil mixture to explode into a gas, all of which was ignited by the smoldering wood shavings and/or hot coals. He claims the device was very unstable and would often set itself off after a few days. He also said the damage it inflicted when it worked properly was massive and total. Sheer devastation. It could take down a horse and its rider in seconds, and covered them in sticky flames. (like napalm?) The technology to me sounds believable, and physically and chemically it makes perfect sense and is more than feasible. The myth is; could something like that actually work? Did it really exist? How effective could it have been? Does this qualify as a landmine?