a yellow and black warning sign in a forest, trees. the sign is attached to a post and has trees in the background. radiation

warning sign forest trees pinus clausa aleppo pine pines evergreens conifers yellow black post signboard nature wilderness outdoors safety danger hazard caution advice notice notification reminder alert announcement information symbol communication first be careful watch out look up radiation landscape chernobyl zone pollution ukraine atomic environment contamination nuclear abandoned catastrophe disaster radioactive triangle