There is Gaan Point in Agat Village.
Ga'an Point in Agat was part of the southern landing site of the United States forces in the liberation of Guam on July 21, 1944. The southern landing area encompassed from Bangi Island to Apaca Point.
You can see the old cannon by the beach here.
Other gun looks like machine gun as below. This is on the right hand side of park.
Back in the war time, the Japanese defense weapons placed at Ga'an Point included a
single-barrel, Japanese, dual purpose 25 mm machine cannon and a 200mm
short barrel naval gun, a 25mm machine cannon, and a double-barreled
anti-aircraft gun, according to National Park Service website. Click below for more detail...
This point also has a clean restroom.
It takes about 32 minutes from Tumon area by car. See the direction below.