Close-up of Fortress Plotting Room (following volunteer restoration works), September 2020

Concealed within coastal bushland at North Head Sanctuary, Manly, the underground Plotting Room is part of North Fort – a historic army base, established in 1936, that once defended Sydney from the threat of invaders. North Fort featured two 9.2 inch calibre guns and target coordinates were relayed to these heavy weapons from the nearby Plotting Room. When the Harbour Trust commenced the Plotting Room Restoration Project in April 2019, the underground facility had been inactive for more than seven decades, during which time it had sustained damage from water ingress, unauthorised access, feral animals and general wear and tear.