Are there other countries other than in the US that gave out sub prime loans?nI mean is it legal in other countries to lend money that is not yours to someone who does not have collateral (like 0 down) and you know has a terrible credit history?

How does the debt system work, what happens when the other countries buy our debt, can they sell our debt to other countries, can they force us to pay our debts at any given time, please explain how the national debt system works?nnThanks, I need lots of details and really want to comprehend so thanks again for your help!