Iran and Afghanistan share a 582-mile (936-km) border along a plain in western Afghanistan.
The Iranian-Afghan border crosses through several deserts and marshlands.
Iran has a population of 66.4 million and it is one of the world’s only Shia-majority states, with Shia Muslims comprising 89 percent of the population or 58.6 million of people.
Iran also has a Sunni Muslim minority, which accounts for nine percent of the population or 5.9 million people.
The Hazara make up roughly nine percent of Afghanistan’s population or 2.9 million people. Fifty-eight percent of Iranians or 38.2 million speak Persian, while half of all Afghans or 16.3 million speak one of several dialects of Persian (Dari).
The Turkmen population in Afghanistan is concentrated mainly along the northern border with Turkmenistan and Uzbekistan.
Over sixty percent of Afghans are under the age of 25.