The Magic School Bus - Gets Swamped - Ep. 43

Walkerville is debating whether to build a mall where the swamp is now, or to build it somewhere else. With the toss of a coin, the class finds themselves defending the swamp and Janet arguing against them. However, they find out that it is home to several organisms, an argument Janet finds little more than a joke, with which the city agrees. That is, until lightning strikes and knocks over a tree, blocking off the swamp and flooding the city. After the crisis is resolved, the city realizes that if it were to build a mall on the swamp, then it would be washed away.