It's a jungle out there. With more than three billion Web pages to sift through, finding great science sites is harder than ever. The good news is the editors at Scientific American have once again trawled the Internet for the best the Web has to offer. We think our list of winners has something for everyone.
Grouped into 10 categories below, our 50 favorites are a diverse lot. Learn everything you ever wanted to know about the abacus, toast Watson and Crick's discovery of the structure of DNA, find out how to patent that invention you've been contemplating. Or maybe virtual stargazing is more your style. Whatever the case, we hope you enjoy these sites as much as we do. As always, if you have a favorite that's not on the list, you can nominate it for a future award. Just send us the url.
Special thanks to Melissa Kirsch and Laura Wright for their assistance in producing this section.