Dame Anna Wintour had just sent off her first edition of US Vogue in October 1988 when the magazine received a phone call from the printers. They had seen the issue's front cover, and had one question: "Has there been a mistake?

After nearly four decades as editor in chief, Anna Wintour is stepping aside from her signature role at Vogue. The 75-year-old will retain global responsibilities at Condé Nast as the magazine searches for a new editorial leader.