Refers to a difficult or complicated situation in which a significant change occurs in the course of events.

Throughout history there have been various crises. One we all know is the economic crisis.

The main reason may be due to this crisis was the financial part of the economy. Mainly it was because of the mortgage and other financial products, particularly those known as sub-prime. This has happened is that people calling credit and mortgage to the bank in order to buy goods such as housing, car, etc.. Then the bank instead of offering less money value of the goods offered its full value and even gave them the possibility to learn more.

In turn, the bank sold small portions of these mortgage to other bank. Apparently this was a good deal, but the problem came when people started to default. At that time the money had been paid was impossible to collect. Also had to join you when the money was paid, the economic situation was good and house prices were high.
But since then the price went down, and what used to cost 1000 now could be worth 900. What would cause the bank could not recover the money lent