After a few test runs, I wanted to share a quick reference for which adaptors and convertors for each country. I'm not electrician by any means, so I'm going to put this in the most basic terms possible to make it easy to understand.
Convertor: This is an object that allows you to plug in a certain voltage electronic into an outlet that operates at another voltage. (Volt: the SI unit of electromotive force, the difference of potential that would drive one ampere of current against one ohm resistance.) Most American electronics operate at 110 volts, but most of the world operates at 220-240, like Europe.
Note: Before you buy a convertor, know that almost all new technology like your iPhone, Apple products, computers, cameras, and such are designed to work at both the 110/120 and 220/240 volt range. It's often your old hair dryers or straighteners that you run into issues of voltage. I've actually never bought a convertor for the 25+ countries I have been to.
Adaptor Plugs: This is the shape of the outlet in which you plug into. Your two prong charger won't fit into the three prong outlet one in say most of Europe. So you need to purchase an adaptor that fits into the local outlet, and allows you to plug yours into it and be charged. It does not change the voltage, but allows you to plug in.
*See end of post for a by country adaptor chart
If you are headed to just Europe, perhaps a single adaptor would be a better fit, or you can get an Universal Adaptor, which is one plug for almost all international destinations. I personally have a few for Europe, and have bought the one off adaptors for destinations like England and Australia.
Most of Europe & SE Asia (except England, Ireland, Malta, & Cyrpus)
THE FULL LIST