TopTen Architecture Sites
American Institute of Architects, architecture lab, Architectural Record, ARCAT, Architect

Barns and Farmsteads
The Barn Journal, Successful Farming, Hobby Farms, Barn Plans

Bridges
Bridges, How Bridges Work, The BridgeSite, Bridge Discussion Forum

Castles
Castles on the Web, Castles of the World, Castles of Britain, Castles and Fortifications of England and Wales

Construction/Remodeling
Builders' Sites, Home Improvement, House Plans, HVAC

Directories of Architects
US, International

HVAC
HVAC Basics, ASHRAE Online, CONTRACTORmag.com, HVAC Pro Forum

Lighthouses
US Lighthouse Society, Lighthouse Forum, The Lighthouse Directory, Lighthouse Getaways

Magazines
Architect, Architectural Record, Arch Paper, ArchitectureWeek, RIBA Journal

Portals
AutomatedBuildings.com, AECCafé, Arazoo

Skyscrapers
Council on Tall Buildings and Urban Habitat, The High-Rise Pages: Tall Over the World, The Skyscraper Center, Structurae

Software
building Analysis, collaboration, design

Sustainable Architecture
Environmental Building News, International Institute for Sustainable Development