Hello everyone
How can I solder a wire into this tiny through-hole? There are no visible copper traces connected to it on either side of the PCB. However, the hole appears on both sides of the board, and the two holes are electrically connected. What's the proper way to solder a wire to it?

 

If there are no traces connected to it, why do you want to attach a wire to it??

 

There are no visible copper traces connected to it

In image *30 there appears to be a narrow trace going south to the big hole.

 

Check continuity, if @Alec_t is right !

 

It looks like he peeled external copper layer and wants to connect to vis because it ties to tracks on inner layers. The via seem to be .006" - .008" at most. This requires steady hand, ver fine wire (awg30..awg42) and then fixing the connection with drop of solder mask