Listing all the countries that are currently at war with each other is actually a curiously tricky thing to do.
First you have to define what an international conflict is, then filter down, and at that point things get rather political.
One of the best attempts at this is Max Gradel's of Metrocosm, which only includes what we'd consider a territorial dispute:
only those disputes that involve ownership of territory.
His version looks like this...Picture: Max Gradel/Metrocosm
...and is the labour of compiling numerous datasets from various sources. It's well worth a look.
We've gone for a solution a bit simpler and mapped all the territories listed by the CIA World Factbook as involved in an international dispute.
It's basically a world map, bar a few notable exceptions.
However, it includes border crossing disputes, such as Mexico, which is listed due to "intensified security measures to monitor and control legal and illegal personnel" from Mexico to the US.
This can hardly be considered a war, but is listed by the World Factbook as an international dispute regardless.
Including these sources of tension, it's therefore unsurprising that in some form or another, every country in the world seems to be at war.