[nehagup]

When I try and imagine what that must be like from the inside—I can’t think of anything more exciting or scary than to gain a new sense.

[LadyCailin]

There is a belt you can wear that has vibrators around it, and it always vibrates the north facing side. I read that people who wore that for a few weeks started gaining the ability to create much more accurate maps in their head, which makes sense, this is how pigeons do it too, they basically can just always sense where north is.

[herbst]

There are magnet Implantats you can put into your finger which lets you feel magnetic fields.

[meindnoch]

That's not a new sense, just using the existing tactile system with a magnet.