Detroit's abandoned tunnel systems open door to another world
While most of the tunnels are now abandoned and closed off to the public ... the Detroit Medical Center holds eight hospitals ...
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Dark truth behind abandoned secret US military base hidden under ice in Greenland with two miles of tunnels
The truth behind a secret US military base that was built into a ... 600 nuclear-tipped missiles in the two miles of underground tunnels that could eventually be aimed at the Soviet Union.