Currently, 15 types of electrical outlines exist—only 12 of which in common use. If you’ve travelled abroad, you’ve likely encountered a few already. Unless you brought an adapter, charging your electronics would have been difficult.

Not only do outlet shapes change country-to-country, but so do the voltages. This means that even if your charger could fit, the power surging through might overload the device.

So what outlets can you expect when travelling the world? Look at the diagram below and each country’s corresponding letter value to find out.

What’s with the Electrical Outlet Varieties?

Ever wonder why the world doesn’t standardize outlets? Well, the reason stems back to Edison.

Edison’s experiments with direct current (DC) power proved ineffective at maintaining voltage over long distances. Thus, Tesla invented alternating current (AC) power to remedy the problem. Unlike Edison, who used 240v, Tesla harnessed only 110v. After Westinghouse Electric bought the patents, the company kept Tesla’s original design for 110v.

Meanwhile, the German company BEW pursued Edison’s 240v level—a preference that slowly swept Europe. Other variants sprouted around the world, but all differences originate from the rivalry between AC and DC power.

Regarding outlet shapes, that came about later. Originally, appliances connected directly to a home’s wiring system. It wasn’t until Harvey Hubbell invented the Separable Attachment Plug that people could plug into sockets for power. The Separable Attachment Plug transformed from two to three prongs over time, but other inventors started working on their own designs. Before long, each country had its own plug to go along with the different voltages available.

More developments occurred during the World Wars; however, the story follows a similar path. It’s unlikely for things to change now, so just embrace the history and travel with a converter.