Amazon Ordered to Hold Another Union Election at Alabama Facility

A Federal Labor Relations official has mandated a second union election at an Amazon warehouse in Bessemer, Alabama, after finding that Amazon interfered with the initial election. The National Labor Relations Board discovered that Amazon compromised the election's fairness by installing a mailbox wrapped in Amazon branding, potentially surveilling employees, and distributing anti-union materials. This new election is part of the ongoing efforts by the retail, wholesale, and department store union to establish Amazon's first organized facility in the U.S.

What was the significance of the mailbox that Amazon installed in front of the fulfillment center?

What is the broader context of the union's efforts at Amazon as mentioned in the text?