The Metropolitan Museum of Art in New York is one of the best in the world, and now, thanks to its website, the wealth of art and art history it holds is some of the most accessible.
Ever confuse your Manets and Monets? Forget which is Jasper Johns, and which is Jackson Pollock? The Met website is indexed by artist, and displays pieces of artists' work, as well as essays that reference it, with just a few clicks of the mouse. There's also a separate subject index, which runs the gamut from "Abstract Expressionism" to "Zodiac."
It would be easy to spend hours delving into the interactive Timelines feature, which summarizes not just art history, but other major historical periods and events. The timelines become more detailed with every subdivision. For instance, want to know about artists in Western and Central Sudan during the middle ages? French art during the 20th century? Done and Done.
Flickr photo by T.SC (cc)

