When I taught high school biology, a favorite part of the curriculum was cellular structures and functions. I set up an activity suggested by other experienced biology teachers that was based on the “Cell City,” a learning analogy where students would create an artwork of a city with the mitochondrion as a power plant and a vacuole as a lake. (Figure 1) I wish I saved their very creative projects, but I distinctly remember one group used the Chicago Transit Authority’s elevated train system map to represent the endoplasmic reticulum (ER), a very clever use of the analogy and a nod to city pride. It was also the first time these students really thought about vesicular transport, although they didn't fully understand its importance.