Memorial to U.S. Marines who fought in the Battle of Iwo Jima:
A small, wooden board staked into the ground next to the flag-raising site on Mount Suribachi’s summit carries rank insignia and military devices visitors have left to pay homage to those who fought the battle.
The board can be found behind the American memorial.
And for those whose public/private education has not included Iwo Jima: Iwo Jima
H/T: wikipedia:Iwo Jima Homage_Insignia Devices