The USGS‘s California Seafloor Mapping Program has produced a set of insanely detailed maps of the sea floor along the California coast. Downloadable as rather hefty PDF files; the map sheets are three feet across as paper maps. Above, a detail from the shaded-relief bathymetry map of the San Francisco area. Boing Boing, Wired.
A couple of supremely detailed rail maps to bring to your attention, both of which show every line and station of long-distance, regional and commuter rail networks. There’s one for California, which uses a Beck-like, diagrammatic design, and one for the Northeast Corridor (see above), which opts for geographic accuracy. Despite the differences there’s a lot of overlap on the two design teams. Creative Commons licensed, with printed posters available.
