Preserved bodies of humans and animals have been discovered in bogs in England, northern Germany and Denmark. Records of such finds go back as far as the 18th century. However, it is only in the 20th century that the technology exists to determine their age. It isn't readily apparent if a body has been buried in a bog for years, decades or centuries.
Unlike most ancient human remains, bog bodies have skin and internal organs as well as skeletons. Scientists have been able to study their skin, reconstruct their appearance and even determine what their last meal was by their stomach contents.
Many bog bodies show signs of being deliberately buried in the bog. Forensic examinations of some bog bodies suggest they were ritually slain and placed in the bog as part of the ritual, possibly as an execution, possibly as a human sacrifice.