Enlarge Image MOLA Headland

London is in the midst of a major sewer project and a construction site just turned up something very unusual: a medieval skeleton found face-down in the mud of the Thames river. The remains included a pair of thigh-high leather boots still on the body.

The MOLA Headland Infrastructure archaeology consortium announced the find this week. Scientists dated the male skeleton to the late 15th or early 16th century.

Enlarge Image MOLA Headland

The skeleton's face-down position, combined with the arms being at unusual angles point to an accidental death rather than a deliberate burial.

"These clues could suggest that he fell or drowned and was covered quickly by the ground as it moved with the tide," says MOLA Headland.

The tall boots may have been waders meant for stepping out into the mud and water of the Thames. The boots were made with reinforced soles and an as-yet-unidentified moss-like material possibly meant to increase warmth or improve the fit.

"Leather was expensive and often re-used at this time and experts believe it is unlikely that someone would have been buried wearing such a highly-prized item," says MOLA Headland.

The archaeologists say the man was likely under the age of 35 and suffered from osteoarthritis. The skeleton's teeth have deep grooves that may point to his being a fisherman or sailor who passed rope between his teeth while working.

The skeleton's discovery location was downstream from the Tower of London, at a site where a tunnel boring machine is scheduled to dig out space for a super sewer in 2019. The Thames Tideway Tunnel is meant to reduce sewage pollution in the river.

This rare archaeological find during the process offers a fascinating glimpse into the river's human history, and just how dangerous it could be to make your living on the water.

CNET's Holiday Gift Guide: The place to find the best tech gifts for 2018.

Taking It to Extremes: Mix insane situations -- erupting volcanoes, nuclear meltdowns, 30-foot waves -- with everyday tech. Here's what happens.