When students enter the author's classroom on the first day of school, they are greeted with live crabs scuttling around in large bins. The crabs are her way of grabbing students' attention and launching the unit on the Chesapeake Bay watershed. She chooses to start the year with this unit because, despite the fact that the Potomac River can be seen from the windows of the school, few of the students are aware that they are an integral part of the Chesapeake Bay watershed. The goals of this unit are to teach students about the bay, the watershed, the organisms that live there, and human impact on the ecosystem. Through a variety of experiences, students learn about diversity, interdependence of organisms, the relationship of organisms to their environment, and environmental responsibility. (Includes a project sheet, 4 figures, and examples of posters students can create for this project.)