Civil unrest in Syria has sparked the biggest global displacement crisis in over two decades and a heated debate among European leaders over how many of the thousands of refugees to take in. German Chancellor Angela Merkel has championed quota system for EU countries rehoming refugees while Britain has resisted taking any more than 20,000 Syrian refugees over five years. As the politicians squabble it's worth keeping in mind the huge distances migrants travel to get to Europe through Africa and the Middle East, along well-worn routes. These graphics from Reuters put that in perspective. They also show how central Turkey and Greece are to the migrants' routes (green lines). The countries act like bottlenecks. Once they get to the shore of the Mediterranean, the journey gets even more dangerous and deadly. Last year more than 3,000 migrants died trying to cross. The migrants aim for the mainland mostly, hitting Spain, France and Italy but avoiding Sardinia, right in the middle of the sea. Join the conversation about this story » NOW WATCH: 50 Cent testifies his lifestyle is an illusion