Earth seems to have some places where there are some signs of an ancient technological civilization who used powerful weapons whose effects are still lingering in the landscape. There are some sites where rocks have melted into strange shapes, or sand melted into glass. I came across some stories where there are also indications of radioactive residue, or some other kind of radiation, that is still lingering in the places of impact. It gives us some food for thought that our planet has not always had a peaceful past, and that we still have to watch out for certain places contaminated with some type of harmful radiation.
Read more in my article of The Lingering Effects of Ancient Warfare.