It's not hard to get into Raqqa. The problem, one prominent activist tells CNN, is getting out.
Abu Ibrahim al-Raqqawi's voice is calm and measured as he describes life inside the city ISIS claims as the capital of its so-called caliphate. But the horrors he details are harrowing.
Airstrikes. Executions. Forced blood donations and marriages to ISIS fighters.
Al-Raqqawi isn't his real name. It's the identity the former medical student who helped found an activist group called "Raqqa is Being Slaughtered Silently" uses to speak out. ISIS fighters have already tortured and executed one member of the group, he says, and they've made it clear they want the others involved dead.