Shiite fighters and Sunni fighters, who have joined Shiite militia groups known collectively as Hashid Shaabi ("Popular Mobilization") to fight the Islamic State, gesture Tuesday next to former Iraqi President Saddam Hussein's palaces in the Iraqi town of Ouja, near Tikrit. Thaier Al-Sudani/Reuters/Landov hide caption

itoggle caption Thaier Al-Sudani/Reuters/Landov

Shiite militiamen pose with their banner (right) next to a captured — and upside-down — ISIS flag (left) in Tikrit, Iraq. Militias are bolstering Iraqi forces in a major operation to retake the city from the self-proclaimed Islamic State. Mohammed al-Mozani/AP hide caption

itoggle caption Mohammed al-Mozani/AP

Iraq's push into Tikrit follows its retaking of the nearby town of al-Alam on Tuesday. There, a woman welcomed a relative who is fighting with a militia that's backing Iraqi troops. Thaier al-Sudani/Reuters /Landov hide caption

itoggle caption Thaier al-Sudani/Reuters /Landov

Dura Europos, a Roman walled city in eastern Syria, dates back to 330 B.C. The main gate is shown here in a photo from 2010. It's one of the many important archaeological sites militants of the self-styled Islamic State have ransacked and damaged. EPA /Deir Ezz-Zour Antiquities Department/Landov hide caption

itoggle caption EPA /Deir Ezz-Zour Antiquities Department/Landov

Iraqi security forces and Shiite fighters fire artillery during clashes with ISIS militants in Salahuddin province. The push to retake Tikrit is being aided by Iran, which is providing rockets and other support to Iraq. THAIER AL-SUDANI/Reuters /Landov hide caption

itoggle caption THAIER AL-SUDANI/Reuters /Landov

Members of Iraqi security forces drive toward an area south of Tikrit, Iraq, over the weekend. An Iraqi force has launched a military offensive, hoping to push ISIS out of Tikrit. AHMAD AL-RUBAYE/AFP/Getty Images hide caption

itoggle caption AHMAD AL-RUBAYE/AFP/Getty Images

Then-U.S. ambassador to Iraq Christopher Hill (right) tours the Mosul Museum of History in May 2009. This week the self-declared Islamic State posted a video online that showed militants going through the museum, pushing over statues and smashing artifacts with sledgehammers. Mujahed Mohammed/AFP/Getty Images hide caption

itoggle caption Mujahed Mohammed/AFP/Getty Images

An Iraqi child who fled fighting between the so-called Islamic State and Kurdish peshmerga is among the some 3,000 people living at the Baharka camp, near Irbil, the capital of the Kurdish autonomous region in northern Iraq, on Jan. 16. Safin Hamed/AFP/Getty Images hide caption

itoggle caption Safin Hamed/AFP/Getty Images

Traditional desserts, like these served in 2010 at the original Naranj restaurant in Damascus, offer sweet, familiar flavors at the restaurant's various locations in the Middle East. A platter like this shows up at the end of every meal at Naranj, and all the pastries are made in-house. Jan Smith/Flickr hide caption

itoggle caption Jan Smith/Flickr

Kurdish Peshmerga fighters take positions on the outskirts of Mosul on Jan. 26. The U.S. military says an offensive to drive the Islamic State out of Mosul is expected around April or May. Azad Lashkari/Reuters /Landov hide caption

itoggle caption Azad Lashkari/Reuters /Landov

Training at a new camp near the front line, a mix of Arabs and Kurds prepare for an assault on Mosul in upcoming months. The men will wear balaclavas to conceal their identities while they fight, because they have family in Mosul and don't want to put their relatives at risk. Ari Shapiro/NPR hide caption

itoggle caption Ari Shapiro/NPR

Iraq is preparing to take back Mosul, a senior U.S. military official says. Earlier this month, government-backed Sunni Arab tribesmen who've been training to fight ISIS marched northeast of Mosul, in northern Iraq. Yaser Jawad/Xinhua /Landov hide caption

itoggle caption Yaser Jawad/Xinhua /Landov

Saudi Arabia's Prince Turki al-Faisal, shown in 2013 in Bahrain, says the 'pinpricks' against the Islamic State have not been effective. The former intelligence chief also says the campaign needs to be better coordinated. Mohammed Al-Shaikh/AFP/Getty hide caption

itoggle caption Mohammed Al-Shaikh/AFP/Getty

Before ISIS attacked it, the northern Iraqi town of Snuny had a population of nearly 150,000 — a mix of Kurdish Muslims and Yazidis, who belong to a religious ethnic minority in this region. Only about 10,000 have returned after Kurdish fighters reclaimed the city. Ari Shapiro/NPR hide caption

itoggle caption Ari Shapiro/NPR

The temple of Sharfadin in Northern Iraq is 800 years old, and followers of the Yazidi religion consider it one of the most sacred sites in the world. Though ISIS tried to destroy it, a small group of Yazidi fighters kept the shrine standing. Ari Shapiro/NPR hide caption

itoggle caption Ari Shapiro/NPR

An Iraqi man inspects the remains of what are believed to be members of the Yazidi minority, in the northern village of Sinuni on Feb. 3. Safin Hamed/AFP/Getty Images hide caption

itoggle caption Safin Hamed/AFP/Getty Images

NBC's Brian Williams, seen here on Nov. 13, 2014, has apologized for incorrectly saying he was aboard a helicopter in Iraq in 2003 that was hit and forced down by enemy fire. Julio Cortez/AP hide caption

itoggle caption Julio Cortez/AP

NBC News anchor Brian Williams with his daughter, actress Allison Williams, and his wife Jane Williams at HBO's "Girls" fourth season premiere party in New York. Evan Agostini/AP hide caption

itoggle caption Evan Agostini/AP