Yazidis are predominantly ethnic Kurds whose religion blends elements of Zoroastrianism, Judaism, Christianity and Islam.
Small communities of Yazidis can be found in Syria, Turkey, Georgia and Armenia, but the majority of the estimated 100,000 believers live in Iraq. Most Yazidis, even young people, choose to live in these isolated communities, though they often face extreme poverty.
Yazidis worship an angel figure, Malak Ta'us, or Peacock Angel, who is considered to be the devil by some Muslims and Christians. Yazidis - who don't believe in hell or evil - deny that.
Many Yazidi rituals center on Sheik Adi, a Sufi Arab who lived in northern Iraq in the 12th century and is considered the religion's chief saint. Pilgrims hold festivals near his tomb, north of Mosul.
Many Yazidi traditions are shrouded in such secrecy that most have never been witnessed by outsiders.
Yazidis regard marriage outside their faith as a sin punishable by ostracism or even death to restore lost honor.