The United States and Iran are due to hold their second round of nuclear talks on Saturday, as what both sides are looking for in a deal begins to take shape.

That the talks are even happening represents a historic moment, given the decades of enmity between the two countries since the 1979 Islamic Revolution and the U.S. Embassy hostage crisis.

Iran and the United States plan to meet over Tehran's rapidly advancing nuclear program again next week, after both sides said they made progress in their talks Saturday in Rome.