The great euro-crash of 2012

We can say that the official start of the current crisis was in 2008. But since then, the crisis is suffering of many stages and many mutations. What started as a crisis only in the financial sector, quickly spread to another sectors, arriving to the States.
2012 was a terrible year for all the world but with stongest consequences for Europe, specilaly for the eeuro-zone. We watched many news about that, and each one much more worse than the previous. But what really happened in 2012 in all our economies? And how do we became to this situation?
Here is a video that tries to explain that.