I was searching for the sidi rezegh airfield, then instead I found a huge strongpoint just south of the El Adem airport, with lots of concrete bunkers and trenches, probably built by the germans, as there are many tobruk bunkers. Linked up to the strongpoint, there is also two anti aircraft strongpoints, on the left side of the marker, by the west.
The strongpoint coordinates: 31.784719, 23.875280
The defensive line of Tobruk: 31.950538, 23.980437
A trench line east of El Adem, there are trenches north and south from the mark: 31.853251, 24.074498
The Bir Hakeim strongpoint: 31.593915, 23.479609