Who are the Houthis and how are they making a power play in Iran-US war?

Oil topped $100 a barrel for the first time since May after Yemen's Houthi rebels targeted Saudi ships in the Red Sea, threatening to cut off another route for oil exports already choked by the effective closure of the Strait of Hormuz. CNN's Nic Robertson explains who the Iran-backed rebel group is. Read more at the link in our bio.