One Direction is marking a major milestone! The boy band — which includes Harry Styles, Niall Horan, Liam Payne, Louis Tomlinson and Zayn Malik. celebrated its 10-year anniversary on Thursday and took to social media to reminisce on their time together. One Direction was formed by Simon Cowell on in 2010. Malik left the group in 2015, and the remaining members went their separate ways shortly thereafter. «I’ve been struggling to put into words how grateful I am for everything that’s happened