Millions of Iranians cast ballots Friday in elections to replace incumbent President Mahmoud Ahmadinejad, a race that is being characterized as a potential challenge to the country's ruling Islamic clerics.
A slate of conservatives tacitly backed by Supreme Leader Ayatollah Ali Khamenei are facing off against the lone moderate, Hasan Rowhan, a former nuclear negotiator.
Other candidates include Saeed Jalili, also a nuclear negotiator; Tehran Mayor Mohammad Bagher Qalibaf; and Khamenei's diplomatic adviser, Ali Akbar Velayati.
Look through a series of 15th-century woodcuts, and you'll find that the leper is as much an icon of medieval art as the crown or the cross.
Leprosy was so common in Europe during the Middle Ages that it's estimated 1 in 30 people was infected with the bacteria. But by the turn of the 16th century, after the Crusades had swept across Europe, the disease mysteriously disappeared. And it never returned.
This left scientists puzzled. Did the bacteria mutate to become less harmful, or did Europeans become resistant to the germs?