With the sad news of Wangari Maathai's death on Sunday night (25 September), we celebrate the life and philosophy of an extraordinary woman via a series of video clips, below.

Maathai, a veteran Kenyan activist, wielded global influence with her vision of economic and social progression in Africa running parallel to environmental protection.

Her ground-breaking Green Belt Movement was founded in 1977 and planted tens of millions of trees across Africa while also empowering women living there with new skills and employment opportunities.

Her work quickly expanded to include tackling corrupt politicians and warring factions, both in her native Kenya and beyond.

Her fearless campaigns to stop politicians from seizing land in Kenya made her a national hero, while her Green Belt philosophy became particularly pertinent in areas such as the Congo Basin, where conflicts were closely connected with scarce natural resources.

In 2004, Maathai became the first African woman to be awarded the Nobel Peace Prize for "unique forms of action [that] have contributed to drawing attention to political oppression – nationally and internationally."

In tribute to Maathai's impressive legacy, take a look at these videos of some of her most important messages at conferences and conventions around the world..

ABOVE: Wangari Maathai talks through her ground-breaking Green Belt Movement, which has planted tens of millions of trees across Africa since its inception in 1977.

ABOVE: Wangari Maathai sends a message on Climate Change at the G8/G20 summit in Toronto, Canada, in 2010.

ABOVE: Wangari Maathai explains how money alone cannot help - and in some cases exacerbates - Africa's problems at an address in Los Angeles in April 2009

ABOVE: Wangari Maathai speaking at the Ashden Awards ceremony in 2008. The awards champion local energy solutions to protect the environment, reduce poverty and improve people’s lives.

ABOVE: Wangari Maathai discusses the relationship between scarce natural resources and global conflict at a conference in Berkeley, California, in October 2006.