how can i unblock facebook?

[Breet]

You might need to setup VPN on your system. There are few countries like iran, china and others where facebook is blocked and you should setup VPN in order to access to your favorite social media sites. You can try free vpn services to unblock facebook here http://goo.gl/Fqryiu

But i recommend you to avoid free vpn as it might compromise your anonymity and privacy at time.
Instead of free vpn, you better choose vpn from cheap but top vpn services and unblock not only facebook but all geo-restricted sites with maximum anonymity and online privacy and no one will going to catch you. http://goo.gl/g0VqoM