It's Implementation Day for the Iran nuclear deal.
That means Iran will have verifiably cut down its nuclear program enough that it can get some sanctions relief in return. It's outlined in the Joint Comprehensive Plan of Action, or JCPOA.
U.S. Secretary of State John Kerry and Iranian Foreign Minister Javad Zarif met in Vienna to finalize the details.
Sanctions have punched a pretty big hole in Iran's economy. By lifting them, Iran's shipping, financial, precious metals and, perhaps most importantly, energy sectors will all be open.
That means Iranian oil will add to an already massive global oil glut.
Lifting financial sanctions will also unfreeze tens of billions of dollars worth of frozen Iranian assets as well — something opponents of the deal have been critical of.
Not all of the sanctions have been lifted, though. Iran will have to maintain a peaceful nuclear program for up to eight years before the rest will go away.