How did the lending practice of "derivatives" contribute to the collapse of the banking industry. What is a derivative? How do they work and why did they affect the entire lending industry? Who was to blame?

Some resourses to use:

http://www.youtube.com/watch?v=r66MMYyz9VI

http://georgewashington2.blogspot.com/2008/11/citibank-is-third-largest-holder-of.html

http://www.forbes.com/sites/billconerly/2014/07/17/why-is-the-euro-high-on-foreign-exchange-markets-in-2014/

http://www.youtube.com/watch?v=vcTE5Ek1Qck&feature=related

http://www.worldfirst.com/uk/blog/world-economy/global-currency-outlook-2015/

http://www.nbcnews.com/news/world/g-20-economic-summit-opens-amid-sluggish-growth-trade-disputes-n642601

**Please indicate source used, and has to be at least 300 words**