While most of the tunnels are now abandoned and closed off to the public ... the Detroit Medical Center holds eight hospitals ...

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.

An abandoned hospital that became an attraction for YouTubers and thrill-seekers who explored its empty and graffitied halls could be demolished "within a year" after sitting derelict for decades, ...