Thousands of Amazon workers around the world began striking on Black Friday in order to receive improved pay and working conditions.

Organized by UNI Global Union and Progressive International, the demonstrations aim to hold Amazon accountable for alleged labor abuses, environmental harm, and anti-union practices. Workers in major cities across the U.S., Europe, and Asia will join protests supported by unions and advocacy groups.

Amazon workers in more than 20 countries plan to strike and take part in protests starting on Black Friday, one of the biggest annual shopping days for retailers. The protest efforts will go on into Cyber Monday, one of the biggest online shopping days of the year.