Demonstrating the power of real-time data mining, map design, and collaboration, the Atlas in a Day Challenge asks participants to create maps based on a one-word theme to be compiled into an atlas–all within 24 hours. This one-day challenge will begin with the reveal of the atlas theme at the NACIS Business Lunch. Enjoy the camaraderie of your fellow NACIS guerrillas as we collectively build and compile our crowdsourced atlas narrative. The final atlas will be available as a free, downloadable PDF on Guerrilla Cartography’s website, with a print version offered at cost to participants after the event.