The Museum of History & Industry (MOHAI) is a history museum located in the South Lake Union neighborhood of Seattle, Washington. MOHAI is the largest private heritage organization in the State of Washington maintaining a collection of nearly 4 million artifacts, photographs, and archival materials that primarily focus on Seattle and the greater Puget Sound region. A portion of this collection (roughly 2% at any given time) is on display in the museum's galleries at the historic Naval Reserve Armory in Lake Union Park. Highlights include Boeing's first commercial plane, the 1919 Boeing B-1; the Petticoat Flag, an 1856 American Flag sewn by women during the Battle of Seattle; and the Rainier Brewing Company's 12-foot tall neon "R" sign. In addition to both permanent and temporary exhibits, MOHAI administers ongoing youth and adult programming, and regularly hosts public events in partnership with other community organizations, particularly within the South Lake Union neighborhood.