The strategic waterway of the Strait of Hormuz - through which roughly one-fifth of the world’s oil and liquefied gas normally flows - has become a central flashpoint in the US-Iran conflict, with global markets hanging in the balance. After closing the Strait to most international traffic at the start of the war, Iran has proposed allowing ships to sail freely along the Omani side of the channel, contingent on a wider negotiated peace with the United States.