Why can 2008 be an Example of a Market Bubble? What happened?

-2008 saw a Speculative Bubble in the US Housing Market crashing down. The Growth in the 'Sub Prime' Mortgage Market (Risky Mortgage Lending) led to House Prices Rising -As they got more Expensive, people started to Default on their Mortgages as it got too Expensive -Eventually, in 2008, the Bubble had been too big and Popped, when too many people had Defaulted, leading to House Prices Crashing -Bank's Assets Sheet had reduced Severely and had to Cut Lending creating a Credit Crunch -This lent itself to a Loss in Confidence overall in the US and Europe, leading to a Deep Recession