REPORTER CHRIS BURY: "In the canyons of downtown Houston, home to the country's energy giants, a sense of gloom surrounds this one. Only months ago, it was the mightiest of them all. [Phone rings] Now Enron answers the phone with this recorded message.”

ENRON PHONE MESSAGE: “On December second, Enron filed under the Chaper Eleven of the Bankruptcy Code, thus commencing proceedings to stabilize our financial situation.”

It was at that time the largest bankruptcy in American history. Ten thousand people lost their jobs. Some Enron investors lost all their money in the failure. Former employees lost the retirement payments they needed to live on. Some top Enron officials were found to have used dishonest accounting methods to hide financial problems from investors.

Enron's troubles also involved two large banks, Chase and CitiGroup, and a big financial company, Merrill Lynch.

CARL LEVIN: "Enron couldn't have engaged in the deceptions it did without the help of a major financial institution. Merrill Lynch assisted Enron in cooking its books, by pretending to purchase an existing Enron asset, when it was really engaged in a loan.”

Senator Carl Levin led a hearing into accounting and consulting practices and how they benefited Enron. Those actions included inflating the value of the company's stock.

The collapse of Enron was followed by a series of other corporate failures linked to dishonest accounting methods.