A Span For All Seasons: David Denenberg provides photographs of bridges and a large inventory of suspension bridges.
Bridges: Great Buildings Online provides images and information on a selection of famous bridges world-wide.
Bridges of the World: Photographs and histories from Glass, Steel and Stone of famous bridges historic and modern.
Digital Bridges: Online library of historical bridge design manuals and books from Lehigh University.
Historic Bridge Foundation: Advocates for the preservation of historic bridges. Includes Texas and New Mexico bridges.
Living Bridges: Illustrated review by Yoshitaka Mouri in Art Watch of the Royal Academy of Arts exhibition on inhabited bridges, including historical examples and past utopian bridge plans.
Pons: Article from Smith's Dictionary of Greek and Roman Antiquities 1875. Illustrated with the original woodcuts.