Natural ecosystems provide many valuable services including the maintenance of biodiversity, the control and purification of rainwater, and the provisioning of food and habitat space, on which humans rely. Humans can fundamentally change natural ecosystems in many ways, including through urbanization: the building of cities. However, many of the services that natural ecosystems provide are still needed in cities. It is the challenge of urban ecologists to understand cities as ecosystems and work to restore and protect necessary functions for the good of humans and their environment. In this course, students will work to understand the ecology of New York City, the most populous city in the United States. This ”mega city”, once a ecological hotspot, now serves the the needs of over 8.5 million people. Students will visit sites throughout the city that are built to provide services like water purification, waste removal, and habitat space. Services that would have previously been provided by the natural environment. The goal of this course is for students to understand how city ecosystems function and how much even a mega city is reliant on and needs to deal with the forces of nature. Students will also gain experience in critical, scientific thinking, the application of principles of natural science, and communication of scientific knowledge.