I'm not sure where this was taken but believe it was somewhere in Thua Thien province.  I remember the patrol distinctly, but can not remember the specific location.  We had humped along a trail for two days, then followed it up the side of a hill to this relatively bare and flat-topped hill where we made our night lager site late in the afternoon.  I had all the machine-gun ammo collected up and laid it down near the gun where it would be easy to find and get to in the dark if needed.  Unfortunately, this slide is beginning to suffer a color shift, making the ground look much redder than it really was.

This is one of the fabled "punji pits."  These pits were dug a foot or two in depth in areas where it was likely a US patrol might pass.  Then large spikes were put in the bottom where the weight of a falling foot would drive the stake through the bottom of the boot and into the foot and the pit was then covered with light sticks and a matting that was then covered with dirt and/or grass to camouflage it. 

The VC and NVA used all sorts of material to construct the actual stakes but a couple favorites were iron and bamboo.  This one and the other one near it both had bamboo spikes in them.  It had been dug along the edge of a well-used trail.  It had been raining for about 36 hours off and on and, luckily, the weight of the wet dirt collapsed it a bit, making it easy to see.  After examining it for booby traps, we completely collapsed it with a rock. 

Here I've propped a couple of the stakes that I'd pulled out of the pit up against another Marine's M-16 so they would be visible and took a picture of them.  They vary in length somewhat but you can see from the relation of the stakes to the M-16 that they are all long enough to do serious damage to a man's foot.