How London's Newest Transit Link Revealed the Source of the Great Plague

London's Crossrail network may not come into service until late 2018, but it's already throwing up some surprises. The new heavy rail service linking London to its exurbs promises to take some of the strain off London's overcrowded Tube. But it has also unearthed long-forgotten burial pits and, by accident, revealed the source of the Great Plague that killed 100,000 Londoners (roughly a quarter of the city’s population) around 350 years ago.

Last year, workers constructing a future new ticket hall at Liverpool Street Station unearthed a charnel pit adjoining the old Bedlam Hospital, in which 3,000 skeletons were interred. Now it turns out that some of these skeletons had the answer to a centuries’ old mystery, hidden away in their teeth.