Double edged razors embedded in plants, trees, or woodwork where people are likely to brush against or grasp.
A nasty little surprise...
Open manholes in tall grass/weeds.
Another reasons not to explore at night and to watch every step you take.
Open wells are fun too
Keep a sharp eye open for eye hazards like a stiff wire at face level.
Best to always wear glasses or safety glasses especially in low light areas.
Rebar that's not bent over and sticking up/out may not be an intentional trap but if you trip and fall on it the results can be lethal.
Be aware of your surrounding art all times and don't goof around in dicey industrial landscapes... always keep your eyes on where your feet are going when moving.
A missing steel staircase in a Atlas F site left me sitting on my ass on the second to last step to oblivion. A 20 foot drop to concrete.
Only fast reflexs and a good grip on the hand railing saved me.
Keep a handheld on hand rails on stairs and catwalks even if you got great balance. Had I not done this I probably been DRT.
Keep your hands, at least one free when moving in unknown terrain.
Shit happens without warning, out of the blue... and it can eventually happen to you.