I recently explored a World War Two remnant located on Hilaan Point on the northwest coast of Guam. This site holds a Japanese AAA (Anti Aircraft Artillery) position, with several gun pits remaining. The fortifications mostly consist of drums filled with limestone rock, stacked on top of each other with additional rocks piled up to form a defensive position. It is very difficult to see anything as you can see in this 360 degree panoramic shot, taken from atop one of the berms:
(warning – large photo!)
You really have to look close to see anything in the grass. In this photo, there appears to be nothing. But, if you look closely, you will see that the ferns in the center of the photo fill up a depression in the ground which is in fact one of the positions.
Look even closer, and you can see two barrels filled with rock on either side of the original entrance into the position.
I was able to find four such positions. Other than the drums and berms themselves, nothing else appears to remain. With the high grass and overgrowth, it would take a grass fire or typhoon to knock back the vegetation enough to see exactly what remains.
I have been able to find almost no information on the site. What type of AAA guns were located here? Was the site attacked by American aircraft or ships before or during the retaking of the island in 1944? Did any land battles take place here as the 3rd Marines moved north to secure the island? unfortunately, I have not been able to answer any of these questions yet. [December 2020 update: There appears to have been a Japanese airstrip under construction just northeast of these defensive positions, at the time of the US landings in June 1944]
I did find a photo of a similar Japanese AAA site taken in October 1944, located on Orote Point further south. This gives an idea of what this site would have looked like then, as both seem to have been similarly constructed.