There are literally dozens of these tools to help you locate what you're looking for. The trick is understanding how they work, so you can use the right tool for the job. Like a card catalog in a library, they classify websites into similar categories, such as accounting firms, English universities and natural history museums. The results of your search will be a list of websites related to your search term. If you are looking for the site for the Louvre museum, for instance, use a directory.
Web indexes are the way to go, because they search all the contents of a website.
Indexes use software programs called spiders or robots that scour the Internet, analyzing millions of web pages and newsgroup postings, indexing all of the words. Indexes like AltaVista and Google find individual pages of a website that match your search criteria, even if the site itself has nothing to do with what you are looking for. You can often find unexpected gems of information this way, but be prepared to wade through a lot of irrelevant information too. This is a much more thorough way to locate what you want. Perhaps you would consult a travel guidebook.