Some Brooklyn Starbucks coffee shops were among the roughly 8,000 locations nationwide that closed Tuesday so employees could undergo anti-bias training.

The four-hour training session is focused on the history of racial discrimination in public places. It comes after a Philadelphia Starbucks manager in April called the police on two black men who were waiting for a friend in the shop without making a purchase. The company's CEO quickly condemned the trespassing arrest, calling the situation reprehensible.

Starbucks chairman Howard Schultz addressed the issue in an open letter to customers, saying that he created the store to be a "third place between home and work to have a coffee, read or just relax."

Schultz and musician Common served as virtual guides in the employee training video. Workers broke into small groups to share life experiences and discuss the realities of bias.

Starbucks has since changed its policy to allow all members of the public to spend time or use the restroom in stores without making a purchase.

The Starbucks at Smith and Wyckoff streets in Boerum Hill closed around 2:30 p.m. Tuesday and will reopen Wednesday morning.