This tweet about the Sunderland sound mirror was a little bit popular!
Delighted to discover Sunderland's sound mirror hidden behind the VW garage in Fulwell. It was built around 1917 to detect Zeppelins after deadly airship attacks on the city in 1916. More info athttps://t.co/Qn1K2qXZ2R pic.twitter.com/H9Wvbwd48d
— Birmingham 81 (@Birmingham_81) January 22, 2018