Cover Stars
Serena Williams Announces Retirement From Tennis in the September Issue of 'Vogue'
She calls the choice "the hardest thing that I could ever imagine."
Must Read: Italian Luxury Goes on Lockdown, What Went Wrong at Outdoor Voices
Also, Tierra Whack covers "Teen Vogue."
Must Read: Gap Names New CEO, the Dixie Chicks Cover 'Allure'
Plus, luxury brands are now advertising all over Twitter.