Our reporter Roee Ruttenberg takes a look at the course of events over the years and sees how Syria has changed after years of conflict.
It began with demonstrations over the arrest of young boys. It quickly expanded into a confrontation with the government.
Pro Bashar al-Assad rallies were also held. But the delicate ethnic and religious balances that held Syria together quickly fell apart. Ancient cities like Homs and Daraa became modern day battlefields.
The fighting bloody town-to-town, street-to-street, house-to-house. The world and the region shocked -- but nations stoked the civil war by taking sides and sponsoring armed groups. The US called for Assad to step down.
By 2012 the fighting was country-wide. The UN sent an envoy. Peace plans were floated - but the killing continued. By 2013 chemical weapons were being used against civilians. This was a red line, the US President declared.
The US seemed poised to intervene- but instead decided on diplomacy with an influential Russia. An agreement was signed to rid Syria of chemical weapons peacefully.
But Syria continued to implode. Syria's second most populous city Aleppo became a flashpoint. Rebels radicalized by war and outside influence became increasingly Islamic in nature.
ISIL rushed in from neighboring Iraq, terrorizing village after village. In the fall of 2014 the US launched an air campaign against the terror group after it shocked the world via social media showing the execution of kidnapped journalists.
Refugees who had flocked to Turkey, Jordan and Iraq by the millions now tried to move to Europe by the thousands risking everything for a better life. The migrants were met with a mixture of hostility and compassion creating deep divisions in Europe. Peace plan after peace plan failed.
2015 and Syria's government forces suffered setbacks- fears of a radical rebel takeover fueled intervention on behalf of Damascus by Iranian backed forces -- and then perhaps decisively, Russia.
Moscow said it was targeting terrorists - just like the US - but the two sides don't agree on who is a terrorist. Serious tensions rose.
2016 saw tensions too between other powers. Turkey, angry at its US ally which relied heavily on Syrian Kurdish forces to tackle ISIL since Kurds have long sought to carve out a separate state from Syrian and Turkish territory.
2017 brought a new US President and a new policy - the US stepped up its fight. Eventually the self-described caliphate's capital of Raqqa would fall. For the first time in the conflict the US launched air strikes in response to an alleged chemical weapons attack by Damascus. Syria denied it, Russia complained and the deep divisions remained over Syria's future.
2018. Russia, buoyed by its success in defending the Syrian government and turning the war around, is now trying its own peace initiative.
But the killing continues. Civilians from the Damascus suburb of Eastern Ghouta trapped -- despite United Nations attempts to facilitate an escape corridor.
After 7 years, nearly half a million people are dead. Another twelve million have fled their homes.
Still, last week, Trump announced he wanted to pull US forces out of Syria immediately. A day later, he said, the withdrawal might take a few months.
But that tone changed this week after Saturday's alleged chemical attack on the residents of Douma.
Early Monday, Damascus said its Tiyas airbase in Central Syria - largely used by Russian forces - was struck by jets. It first blamed the US, which denied it. Then - along with Russia - blamed Israel.
Later in the day, Trump promised a "major decision" would be made on Syria within 48 hours.
Roee Ruttenberg, CGTN.