I wanted to add my remix of Urban Ecology (UE) with a sustainability turn:
Map the plastic! Expand UE by noticing MORE of the impact humans have on the nature around us. Take a field trip to find plastics in the urban wilds, catalog and sort your findings, and create a Google Earth layer that different groups of patrons can add to over time: tweens, teens, adults can make this a one-off or a year-long project.
This is a great way to discover meaning and tie into social-emotional learning, too.
You could also explore the landscape through the lens of Landscape Justice, creating and discovering knowledge of local environmental conditions in poor or redlined neighborhoods.