Oil prices could fall thanks to new pact
Why is this such a big deal?
US and Israeli officials say a nuclear-armed Iran would be a security disaster and potentially lead to war because of Tehran's support for anti-Israel militant groups, such as the Palestinian Hamas and the Lebanese Hezbollah group.
Iran has long maintained that its nuclear programme is peaceful and that it never sought to build a bomb. The talks were mostly considered stalemated until summer 2013, when Iran elected a new president, Hassan Rouhani.
What happens now?
If the UN nuclear agency identifies a suspicious site, it can ask to inspect it. If Iran refuses, an arbitration panel will decide whether the Iranians have to open up the site to inspection within 24 hours.
All of this is aimed at slowing down the rate at which Iran could, in theory, build a nuclear weapon.
In exchange, Iran stands to receive more than $100bn in assets overseas that had been frozen by other countries. It also will see an end to a European oil embargo and other financial restrictions on its banks.
What was the compromise?
Among the biggest concessions by the West is that Iran doesn't have to submit to international inspections anytime, anywhere. Because the process for inspections could end up with an arbitration panel, access to the Islamic Republic's most sensitive sites isn't guaranteed and may be delayed.
Another concern is that a UN weapons embargo could lift in five years or sooner if certain criteria are met. US officials had sought to maintain the weapons ban because they worry that once sanctions are lifted and Iran's government becomes flush with cash again, more military aid would find its way to places like Syria and Yemen.
What does all this mean for oil prices?
Any easing of economic sanctions will likely mean that Iran can sell more oil, which in turn could bring down crude oil prices. In trading yesterday, benchmark US crude oil prices were down.