Location: Glenbrook

AI Generated - Thousands Descend on Secret WWII Mustard Gas Tunnel

Thousands Descend on Sydney’s Secret WWII Mustard Gas Tunnel

Thousands of people walked, ran and cycled through the Lapstone Hill Tunnel during sold-out July and August 2026 open days, prompting Blue Mountains City Council to seek $15 million to turn the WWII mustard gas storage site into a permanent walking and cycling link.

Extra Lapstone Hill Tunnel Open Day Added After Sell-Out

Blue Mountains City Council adds a third open day for Lapstone Hill Tunnel on 2 August after sell-out, but the heritage site will close again until funding secured.