Fighting escalated from there until it was a civil war. Armed civilians organized into rebel groups. The army deployed across the country, shelling and bombing whole neighborhoods and towns, trying to terrorize people into submission. They've also allegedly used chemical weapons, which is a big deal for reasons I'll address below. Volunteers from other countries joined the rebels, either because they wanted freedom and democracy for Syria or, more likely, because they are jihadists who hate Syria's secular government. The rebels were gaining ground for a while and now it looks like Assad is coming back. There is no end in sight.
3. That's horrible. But there are protests lots of places. How did it all go so wrong in Syria? And, please, just give me the short version.
That's a complicated question and there's no single, definitive answer. This is the shortest possible version - stay with me, it's worth it. You might say, broadly speaking, that there are two general theories. Both start with the idea that Syria has been a powder keg waiting to burst for decades and that it was set off, maybe inevitably, by the 2011 protests and especially by the government's overly harsh crackdown.
Before we dive into the theories, you have to understand that the Syrian government really overreacted when peaceful protests started in mid-2011, slaughtering civilians unapologetically, which was a big part of how things escalated as quickly as they did. Assad learned this from his father. In 1982, Assad's father and then-dictator Hafez al-Assad responded to a Muslim Brotherhood-led uprising in the city of Hama by leveling entire neighborhoods. He killed thousands of civilians, many of whom had nothing to do with the uprising. But it worked, and it looks like the younger Assad tried to reproduce it. His failure made the descent into chaos much worse.