Neil Johnson, a University of Miami physicist, developed this mathematical formula to predict insurgent attacks in war zones. Courtesy of Neil Johnson hide caption

itoggle caption Courtesy of Neil Johnson

The larger of the two Buddha statues that towered over the Bamiyan Valley in central Afghanistan. This photo was taken before a 2001 Taliban campaign that destroyed Buddha statues throughout Afghanistan. International teams are now working to restore the sixth century statues. Zaheeruddin Abdullah /AP hide caption

itoggle caption Zaheeruddin Abdullah /AP

Left: LCpl. Kevin Daly during a military operation near Doghaka village in Musa Qala district, Helmand Province, Afghanistan, on Nov. 7, 2010. Right: Ali Mohammad, a 10-year-old refugee from Kandahar Province, stands in front of his makeshift house in the Charahi Qambar refugee camp in Kabul on Feb. 27. Balazs Gardi /Foreign Policy hide caption

itoggle caption Balazs Gardi /Foreign Policy

Tayyeb Agha at a Taliban press conference in November 2001 in Kandahar, Afghanistan. Patrick Aventurier/Gamma/Getty hide caption

itoggle caption Patrick Aventurier/Gamma/Getty

This image provided by IntelCenter on Feb. 28, 2010, shows Humam Khalil Abu-Mulal al-Balawi in a posthumous video message posted on extremist websites. The al-Qaida double agent killed seven CIA operatives when he set off the 30-pound bomb strapped to his body at a fortified base in Afghanistan near the Pakistani border in December 2009. AP/IntelCenter hide caption

itoggle caption AP/IntelCenter

Afghan National Army soldier Mohammed Shadwar gets a bird's-eye view from the rooftop of a mud-walled compound during a joint clearing operation in Helmand province, Afghanistan. As the top U.S. commander in Afghanistan changes, there's a question of whether U.S. policy will shift from one that supports building up Afghan national security forces to one focused on targeting insurgents. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Former President George W. Bush speaks to student from the Youth Exchange and Study program at the White House in 2005. The program began in 2004 and ended for Afghan students this year after half of those enrolled fled to Canada. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

In this file photo from 2010, Ahmed Wali Karzai, half brother of Afghanistan's President Hamid Karzai, gestures during an interview with The Associated Press in Kandahar, Afghanistan. Rahmat Gul/AP hide caption

itoggle caption Rahmat Gul/AP