Over the next four weeks, dozens of archaeologists will unearth thousands of skeletons from a historic building site in central London.
Bedlam burial ground was in use between 1569 and around 1738, and contains the remains of more than 20,000 people. It was named after the psychiatric institution that was located nearby.
The site is now located close to the current Liverpool Street train station and is being excavated for London's new Crossrail project.
Many of the skeletons to be raised belonged to plague victims. Archaeologists hope that the information that can be gleaned from those bones can help scientists today learn how the bacteria that causes the virus has evolved since. An recent outbreak of plague in Madagascar resulted in the deaths of more than 50 people.
Those buried at Bedlam included "non-conformists" — individuals who didn't want or weren't given a Church of England burial — according to Nicholas Elsden, project manager for Museum of London Archaeology. Other Londoners were simply too poor to afford one, and their remains are now mingled with the more politically-minded dead.
The skeletons begin about six feet under the surface, and continue down for another four feet. The coffins have long since disintegrated and the bones have been compacted together by the weight of the life and construction that continued actively above them.
Underneath the layer of skeletons is a medieval marsh, which in turn lies on top of Roman ruins. The Crossrail archaeologists are scheduled to stay on site until September, and hope to have enough time to examine as much of the available history as they can, Elsden told VICE News.
Some of the non-conformists known to be buried at the site include Robert Lockyer, a soldier in Oliver Cromwell's New Model Army who was executed for his part in the Bishopsgate mutiny of 1649, and Dr. John Lambe, an advisor to the Duke of Buckingham who was stoned to death outside a theater in 1628 after being accused of both rape and black magic.
"It's a really interesting period of London's history," Jay Carver, Crossrail lead archaeologist, told VICE News.
"The people that we're encountering here lived through extraordinary times. And what we haven't got really in London from any other excavation is a sample of the population like we have here. So we have a full range of different Londoners, different social groups, different backgrounds. It's going to be incredible to analyse that as a sample of the London population at that time."
Referring to the "specimens" being excavated, Carver added: "We can analyze in terms of the bacteria and viruses they were exposed to, in particular, bubonic plague is still an ongoing problem around the world. Medical scientists use samples to try and track the evolution of these bacteria and understand how they progress and transform, and that's particularly important for modern-day antibiotics, so the ancient samples that we share with microbiologists could give us a chance to better understand those bacteria and how they develop."
The excavation is happening ahead of the area becoming a station for the new Crossrail service, meaning that the archaeologists have a limited amount of time to explore the ground here before it is covered over again. The archaeologists work in two shifts, stay as late as 11pm at night, and are aided by on-site engineers.
On how he felt about disturbing the dead, Carver said this wasn't a major issue, though they "avoid it wherever we can."
"In Britain," he said, "we have the 1857 Burial Act which means you can't disturb human remains without a license and a very good reason." He added: "What we can do when we have to disturb them is treat them with a lot of dignity, respect, and careful excavation as we're doing with the archaeology team here, and then they're going to be reburied. And it wouldn't be the first time that Londoners have been disturbed and reburied."
Elsden added that while only a random sample of the skeletons would be analyzed, they would keep an eye out for abnormalities that might indicate they had uncovered someone particularly interesting. "Anybody with four bullet holes will definitely be examined," he explained.
He added that they had recently unearthed a child with an adult, though it was impossible to tell whether the bodies had been buried together or not.
This year marks the 350th anniversary of London's last "Great Plague." Elsden laughed when VICE News asked him whether contagious trace of the plague might still linger on the bones of the skeletons, before adding that it was a question that gets asked a lot.
"It just doesn't last in the ground that long," Elsden said. "Myself and a lot of the other senior archaeologists wouldn't still be here if it did, because we've been digging plague bits since the 80s."
Important too, he said, are the non-human discoveries that are emerging. In the previous 24 hours the team working on the site have found chunks of a Roman building beneath part of the road, which they believe may date from the 2nd century AD.
At least 370 skeletons and 15 Roman horseshoes have been discovered so far.
This burial ground was located about 100 yards outside of the ancient Roman city wall. Elsden gestured behind him towards where he said Walbrook, a "lost river," is still flowing through a sewer.
Parallel to that, on the opposite side of the burial ground, he pointed to where a former main trade road ran towards and away from the city. "All the goods you can imagine travelled along that road in ancient times," Elsden said. "All the produce of Britain came here."
After examination, the skeletons will be reburied in Canvey Island in Essex. When asked whether there would be any kind of ceremony to accompany this, Elsden said that it hadn't been decided yet but if there was it would have to be "fairly multi-denominational."
"It wasn't a churchyard," Elsden restated. "It was a burial ground for non-conformists. That's why Robert Lockyer and John Lilburne were buried there."
Follow Sally Hayden on Twitter: @sallyhayd