RE: Is the 2nd largest tunnel system in Eastern Europe in Ukraine? World's largest urban labyrinth: Odessa's Catacombs set world record! Used during Nazi Germany. Tourists advised not to enter without a guide.
From one of the photo frames from above FB frames link,
#PlumIsland, #DevilsIsland
Goes back to 1971 in the New York Times.
Above article in New York Times starts out. . .ORIENT POINT. L. I.—Every weekday at 8 A.M., 275 scientists, secretaries, animal care workers, lab technicians and armed guards climb aboard a 108‐foot ferryboat here and head out into the choppy waters off the tip of Long Island's North Fork.
Twenty minutes later, they dock at Plum Island, a highly restricted 800‐acre patch of scrub brush and 15 nondescript Federal Government buildings that, since 1954, has functioned as a Devil's Island for the deadliest animal disease germs known to man.
Visitors are not permitted. Twenty‐four hours a day, guards patrol the island's perimeter in a jeep to warn away boaters who might he attracted by the clean, sandy beach. The nature of the work done on the island makes these and an elaborate net of other security precautions absolutely necessary. Get your OWN Eyes on it. #RealEyesRealize https://www.nytimes.com/1971/10/10/archives/li-lab-deals-in-danger-lab-involved-in-deadly-work.html