Others have pointed out that there were not enough of these loans made to cause a crisis of this magnitude. In an article in Portfolio Magazine, Michael Lewis spoke with one trader who noted that "There weren't enough Americans with [bad] credit taking out [bad loans] to satisfy investors' appetite for the end product." Essentially, investment banks and hedge funds used financial innovation to enable large wagers to be made, far beyond the actual value of the underlying mortgage loans, using derivatives called credit default swaps, collateralized debt obligations and synthetic CDOs.
What financial innovation allows investment banks and hedge banks to make large wagers?
derivatives

The inhabitants of the British Isles have been drinking ale since the Bronze Age, but it was with the arrival of the Roman Empire in its shores in the 1st Century, and the construction of the Roman road networks that the first inns, called tabernae, in which travellers could obtain refreshment began to appear. After the departure of Roman authority in the 5th Century and the fall of the Romano-British kingdoms, the Anglo-Saxons established alehouses that grew out of domestic dwellings, the Anglo-Saxon alewife would put a green bush up on a pole to let people know her brew was ready. These alehouses quickly evolved into meeting houses for the folk to socially congregate, gossip and arrange mutual help within their communities. Herein lies the origin of the modern public house, or "Pub" as it is colloquially called in England. They rapidly spread across the Kingdom, becoming so commonplace that in 965 King Edgar decreed that there should be no more than one alehouse per village.
What color bush did an Anglo-Saxon woman raise to indicate that her ale was done brewing?
green

It is also known as the Wenchuan earthquake (Chinese: ; pinyin: Wenchuan da dizhen; literally: "Great Wenchuan earthquake"), after the location of the earthquake's epicenter, Wenchuan County, Sichuan. The epicenter was 80 kilometres (50 mi) west-northwest of Chengdu, the provincial capital, with a focal depth of 19 km (12 mi). The earthquake was also felt in nearby countries and as far away as both Beijing and Shanghai1,500 km (930 mi) and 1,700 km (1,060 mi) awaywhere office buildings swayed with the tremor. Strong aftershocks, some exceeding magnitude 6, continued to hit the area even months after the main quake, causing new casualties and damage.
How long after the earthquake were aftershocks felt?
months after