A Look at Key Events in Syria Since March 2011

And the cost of 5 years of conflict in Syria

This undated photo, released Aug. 25, 2015, on a social media site used by ISIS militants, which has been verified and is consistent with other AP reporting, shows smoke from the detonation of the 2,000-year-old temple of Baalshamin in Syria's ancient caravan city of Palmyra. Islamic State social media account via AP

As Syrians mark the fifth anniversary of the uprising against President Bashar Assad, here are some of the key events in the conflict:

• March 2011: Protests erupt in the city of Daraa over security forces’ detention of a group of boys accused of painting anti-government graffiti on the walls of their school. On March 15, a protest is held in Damascus’ Old City. On March 18, security forces open fire on a protest in Daraa, killing four people in what activists regard as the first deaths of the uprising. Demonstrations spread, as does the crackdown by Assad’s forces.
• April 2011: Security forces raid a sit-in in Syria’s third-largest city, Homs, where thousands of people tried to create the mood of Cairo’s Tahrir Square, the epicenter of protests against Egypt’s autocrat Hosni Mubarak.
• June 2011: Police and soldiers in Jisr al-Shughour in northeastern Syria join protesters they were ordered to shoot, and the uprising claims control of a town for the first time. Elite government troops, tanks and helicopters retake the town within days.
• August 2011: President Barack Obama calls on Assad to resign and orders Syrian government assets frozen.

Syrian citizens inspect an unexploded barrel of explosives which was dropped from a Syrian forces helicopter, on a street in Aleppo, Syria, on Jan. 19, 2014. AP Photo/Aleppo Media Center, AMC