A bog body is a human cadaver that has been naturally mummified in a peat bog. Such bodies, sometimes known as bog people, are both geographically and chronologically widespread, having been dated to between 8000 BCE and the Second World War. The unifying factor of the bog bodies is that they have been found in peat and are partially preserved; however, the actual levels of preservation vary widely from perfectly preserved to mere skeletons.
Unlike most ancient human remains, bog bodies have retained their skin and internal organs due to the unusual conditions of the surrounding area. These conditions include highly acidic water, low temperature, and a lack of oxygen, and combine to preserve but severely tan their skin. While the skin is well-preserved, the bones are generally not, due to the acid in the peat having dissolved the calcium phosphate of bone.
The oldest known bog body is the skeleton of Koelbjerg Woman from Denmark, who has been dated to 8000 BCE, during the Mesolithic period. The oldest fleshed bog body is that of Cashel Man, who dates to 2000 BCE during the Bronze Age. The overwhelming majority of bog bodies – including examples such as Tollund Man, Grauballe Man and Lindow Man – date to the Iron Age and have been found in northwest European lands, particularly Denmark, Germany, the Netherlands and the British Isles. Such Iron Age bog bodies typically illustrate a number of similarities, such as violent deaths and a lack of clothing, leading archaeologists to believe that they were killed and deposited in the bogs as a part of a widespread cultural tradition of human sacrifice or the execution of criminals. The newest bog bodies are those of soldiers killed in the Russian wetlands during the Second World War.