When the United States and Israel attacked Iran on Feb. 28, Iran retaliated with attacks that effectively closed the Strait of Hormuz. Oil prices spiked worldwide – and the oversized importance of the strait became crystal clear. Here is a look at the strait’s significance in maps and charts. What is the Strait of Hormuz? The Strait of Hormuz is a narrow passage of water between the Persian Gulf and the Gulf of Oman. It is used to transport a number of valuable commodities – most notably, oil.