Kharg Island lies about 25 nautical miles off the coast of Iran, and is the facility from which it ships the vast majority of its oil to the outside world--- 950 million tons per year from the southern facility alone, according to one article.
Seize Kharg Island, and you can basically turn off the tap on the Iranian economy. The government can't pay the basij, so the basij go home. They can't pay for their expensive nuclear facilities. They can't pay for their military.
That's what happened to the Shah in 1979. The revolution dragged on for a year or so, but when the oil workers walked out, the King of Kings became plain old Mr. Pahlavi.
Kharg Island is a hostage facility. It's a shotgun permanently pointed at the head of the person who built it.
Not that I'm advocating any of this, mind you. I merely make the observation that if the Iranian government really piss off any country that could mount a large enough carrier task force--- uh, I guess that would be the USA--- that force needn't bomb Tehran, or nuclear facilities, or anything beyond the minimum amount of suppression necessary to secure the island. (And the island is a large naval base, so it wouldn't be a complete pushover.)
The disadvantage, from the point of view of the world economy, is that the world would have to do without a billion tons of oil per year for however long the crisis lasted. (I wonder if that's why all those bomb-bomb-bomb-iran guys never mention this option--- they're also committed to a petroleum-fuelled economy.) Still, Kharg Island was pretty much shut down during the Iran-Iraq war, thanks to Iraqi air raids, so the world has done without Iranian oil before.
I wonder how many other nations have on-off switches? Certainly Egypt is one--- they became a hostage the second they completed the Aswan High Dam. One sufficiently large bomb behind the dam, and a tsunami carries 99% of the population out to sea. It would be the greatest atrocity in history, but few Egyptians would survive to complain.
Mr. Putin has successfully demonstrated that he can hold Ukraine and much of Europe hostage, simply by turning off the taps that control oil and natural gas.
The US doesn't have any single switches that I can think of--- unless of course someone succeeds in switching off World of Warcraft, the dangers of which this video points out.
Any other hostage facilities you can think of?