EL Education schools have a vision of interdisciplinary curriculum know as expeditions. An expedition is composed of multiple case studies designed to answer some essential question(s). Here are some of the best expeditions I've experienced in my career:
Apportionment & Gerrymandering
Notice that they often revolve around a concrete topic. I've linked some examples above. Great expeditions take a lot of planning and coordination, and often involve fieldwork and expert interviews. A high-quality final product displays elements of complexity, craftsmanship, and authenticity. For example, a product that matches the formats in the professional world (e.g., making a brochure rather than writing an essay, or including a QR code on a poster that links to a website with more information).