Video: Who is fighting in Syria? And why?

This coming spring will mark the fifth year of the Syrian conflict, and the ongoing violence doesn't seem to be coming to an end anytime soon.

Syria's war started in the spring of 2011. Since then, many countries like the United States, Britain, France, Turkey and Russia have joined, especially after the Islamic State in Syria, also known as ISIS, has gained much strategic power, territory and fighters as the conflict evolved.

Watch the video below to understand Syria's complex battlefield and the reasons why this Middle Eastern country is relevant to the world's major powers.