The Boston Marathon bombers are ethnic Chechens. So who are the Chechens? Here's what you need to know...

The Tsarnaev brothers' Chechnya connection - The Week: The Chechens are an ethnic group in the Caucasus region who have been fighting for independence from Russia for four centuries. Most Chechens are Sunni Muslims, many of whom practice in the mystical Sufi tradition; most Russians are Orthodox Christians. But the independence struggle has long been more about nationality than religion. Chechen identity is fiercely independent and anti-hierarchical, and rests on clan honor and — to a great extent — hatred of Russia. Dzhokhar Tsarnaev's high school friends say he rarely talked about his ethnicity, except to quickly correct anyone who suggested he was Russian.