Some of the most important scientific studies are associated with either incredibly large dimensions (e.g., the universe) or extremely small proportions (e.g., the cell). While a teacher's curriculum may often switch from mega-expanses to minutia, they should question how easily students comprehend the change in sizes. This article addresses the crosscutting concept of scale, focusing on microscopic science. Microorganisms and pollen, either modern or fossilized, offer students a glimpse into a hidden "micro world." Pollens and microfossils are abundant, readily providing opportunities for student-led inquiry to address concepts in botany, ecology, fossilization, evolution, and environmental change. The article discusses how the study of microfossils and pollen can be used to focus upon concepts in biology, geology, chemistry, mathematics, economics, art, history, and more. The authors assert that MicroWorld inquiry units such as the one described herein can incorporate reconstruction of ancient environments, solve "mysteries" of crime scenes, and address current issues such as climate change. Perhaps most importantly, microfossils and pollen can address the crosscutting concept of scale from the microscopic viewpoint.