If you're interested in experimenting this, but don't want an implant, you can buy magnetic rings (for your fingers). Why do these exist? Magicians.
They can be non-surgically removed prior to MRIs, instead of during.
They can be non-surgically removed prior to MRIs, instead of during.
As for my favorite EM field there is a nearby street with buried powers lines and transformer boxes at ground level. As you walk the street to the main street each box has a bigger EM sphere and I like to let my hand coast over each sphere. It isn't a sphere per say, but only in the sense that at at certain depth in the field the density (for lack of a better term) becomes high enough that I can feel it and it is like a boundary line