The Marriott Data Breach: How Did It Happen?

Describe the Marriott data breach.

When was the Marriott breach? What caused the Marriott data breach? What was its impact? Who hacked Marriott and why? How did Marriott respond to the breach? Is there a Marriott data breach class action lawsuit? What did the Marriott data breach cost? Has Marriott been fined for the data breach?