Sometimes, rivers switch directions and flow backwards! One of them is the Tonle Sap River in Cambodia, which changes directions every year. And this change closely follows the rainy and dry seasons. During the rainy season, the river grows to fill three times its usual area and flows into the Tonle Sap Lake. But in the dry season, the river gets thinner, and that's when the super-full lake starts flowing into the river, reversing its course. It also helps that there's, like, a slant to the ground under the lake. Local communities depend on this bi-annual flip-flop for fishing and agriculture. But climate change is affecting the pattern. Recent research models suggest that the river will change less drastically in future rainy and dry seasons, which could affect food supplies. But as these models become more accurate, scientists could help predict the next year's river area when flowing in each direction, potentially helping the communities around the river adjust their agriculture plans.