The world’s biggest challenges – from climate change to poverty and social justice – are just that, BIG. What does it take to make a difference? For the third year, students around the world proved that a big difference can start with a small step. Over the course of the most recent academic year, almost 5,000 students across 71 campuses completed a mind-boggling 113,000 small actions, ranging from recycling and taking public transit to volunteering in their communities. See photos and more.