The Strait of Hormuz: The narrow waterway next to Iran is a choke point that handles a whopping one-fourth of the world's maritime oil trade and a fifth of liquefied natural gas shipments. Iran has previously threatened to close the strait. Still, "supply disruption to global markets would be limited even in the event that Iran retaliates against tanker traffic, given the expected US-led efforts to maintain supply through the Strait of Hormuz," Eurasia Group analysts wrote.