Visualising Code Structure in Large Projects?

TheMaccLads asks: "I've recently joined a new C++ project, and it's in a terrible state. There are 100-odd source directories, dozens of libraries, and a couple of dozen executables and DLLs. Some executables pull in (i.e. compile themselves) the occasional source file from a library, instead of using the libraries. My job is to port a subset to unix, but I need a tool to visualise all the relationships between directories, projects, libraries, and so on, because my brain will overheat soon otherwise. Preferably a tool that will do it by parsing the MS Dev studio projects and workspaces, but if I have to write it myself in Perl, I will! Anyone know of any tools? Or suggest an approach?"