Built in 1904 for local timber barons Michael and Timothy Riordan, this 13,000-square-foot mansion -- Arizona's finest example of an Arts and Crafts-era building -- is actually two houses connected by a large central hall. Each brother and his family occupied half of the house (they had the rooflines constructed differently so that visitors could tell the two sides apart). Although the mansion appears to be built of logs, it's actually just faced with log slabs. Inside, mission-style furnishings and touches of Art Nouveau styling make it clear that this family was keeping up with the times. The west wing of the mansion holds displays on, among other things, Stickley furniture. Guided tours provide a glimpse into the lives of two of Flagstaff's most influential pioneers.