Doutzen Kroes walks the runway during the "Le Defile L'Oreal Paris" Show as part of Paris Fashion Week on September 28, 2019 in Paris, France.

Supermodel Doutzen Kroes has graced the covers of Vogue, Glamour and Harper's Bazaar, as well as representing some of the world's biggest fashion and beauty brands. However, she told CNBC Make It that it's her conservation work with elephants that has given her the most satisfaction.

She said that starting the social media-led fundraising campaign #KnotOnMyPlanet in 2016 had given her "more of a purpose."