The incredible life of Melinda Gates - one of the world's richest and most powerful women

Melinda Gates is best known as Bill's other half. Some may even say she's his better half.

Melinda - who shares an estimated fortune of $89.4 billion with her husband - has become one of the most powerful female philanthropists in the world as co-chair of the Bill and Melinda Gates Foundation, which she helmed virtually on her own for the first six years of operation.

In addition to the pair's education and healthcare initiatives, Melinda takes a personal interest in women's issues around the world. At the forefront of her agenda is expanding the availability of contraception and, most recently, bringing awareness to the concept of time poverty - the notion that hours of daily unpaid work like household chores end up "robbing women of their potential."

"When you invest in women, you invest in the people who invest in everybody else," she wrote in a Fortune article last year outlining the benefits of hiring women in business. "And if you gradually start to take action, it won't be long before you realize that investing in women is good for your mind, good for your soul, and good for your business."

On International Women's Day, a celebration of women's progress and achievements, here's a look at the incredible force that is Melinda Gates.