Bog bodies (also known as Bog People) are cadavers that have been naturally mummified with a peat bog. Unlike most ancient human remains, bog bodies have retained their skin and internal organs because of the unusual surrounding area conditions like
- highly acidic water
- low temperature
- lack of oxygen
The organs may be completely preserved, but the bones have not been so lucky due to acid being in the peat that disolved the Ca3(PO4)2 in the bones.
Tollund Man (the bog person in the pictures) dates back to the Iron Age. Archaeologists believe that iron age bog people were killed and deposited in the bogs as a part of a widespread cultural tradition of human sacrifice or execution since they were mostly found having no clothing on, violent deaths and sometimes tied up.