The BBC's senior international correspondent Orla Guerin has travelled to the edge of the Strait of Hormuz in Oman, which Iran has put a stranglehold on since the war broke out.
The critical artery is normally used for 20% of the world's oil and liquefied natural gas.
By leaving ships stranded in the waterway, Iran is reducing the global supply of oil, driving up prices and creating fear among consumers as well as amplifying pressure in the international community.
Filmed by Lee Durant, edited by Jake Lapham