This site provides links to on-line UK herbarium resources and contains lots of useful information. There are on-line gazetteers, a handwriting query page, systematic look-up lists (e.g. Kent's List of Vascular Plants of the British Isles) and a collaborative database which ultimately aims to combine the data from all UK and Irish herbaria.
The permanent collection of architectural, engineering and landscape documentation at the Library of Congress consists of measured and interpretive drawings, large-format black and white and color photographs, written historical and descriptive data, and original field notes. The collection captures the American experience through approximately 40,000 recorded historic structures and sites, from American Indian cliff dwellings at Mesa Verde to space-age technology at Cape Canaveral.