WW1 Soldiers Holding Human Skulls Massacre? Bone Pile Photo Antq

Description

Very unusual and rare photo of four American soldiers standing on a giant pile of human bones. Two are holding human skulls and femurs in the skull and crossbones pattern. Another appears to be tossing a human skull at the photographer. The fourth is holding large bones.
I am not sure if this is Spanish American war or WWI vintage. The large pile of bones is seemingly from a past massacre. The soldiers have come across it and found a photo opportunity. I have read a lot of history but never about anything like this.
About 4" x 4.5" overall. Faded as shown. A rare photo that invites further research.