The Templar Tunnel is a remnant of the Templar Order that operated in Acco from 1187 when the Templars were expelled from the Temple Mount in Jerusalem.
The tunnel that was built under the fortress passes through the streets of the city of Acco, from the citadel to the port of the town on its eastern side.
Much of the tunnel was renovated and reconstructed in the early 2000s, and today it is possible to visit and observe a unique audiovisual experience, which tells the story of the tunnel and the Templars in Acco and reveals quite a bit of the life of the inhabitants of Acco during the Crusader period.
Image credit: Yasser Shohana. From PikiWiki website.