Back before the 2008 credit crisis, Sal was perplexed by why housing prices were going up so fast and theorized that it was a bubble forming (he was right).
These pre-2008 videos are fun from a historical point-of-view since they were made before all the poo poo hit the fan.
In the fall of 2008, it became clear that a cascade of bank failures was happening because of shoddy loans and exotic securities (both which fueled a now popping housing bubble). In an attempt to avoid a depression, the Treasury Secretary (Hank Paulson) wanted to pour $1 Trillion into the same banks that had created the mess.
This tutorial walks us through the beginnings of the mess and possible solutions. Historical note: it was created as the crisis was unfolding.