Coffeehouse chain Starbucks has announced to shut its over 8,000 stores in the US on May 29 to conduct anti-bias training. The move comes after the firm had to apologise over last week's arrest of two black men who were waiting to meet someone in a Starbucks in Philadelphia. Starbucks' chief executive Kevin Johnson said he had been "learning what we did wrong and the steps we need to take to fix it".