From their website:
The Timeline of Art History is a chronological, geographical, and thematic exploration of the history of art from around the world, as illustrated especially by the Metropolitan Museum of Art’s collection. The Museum’s curatorial, conservation, and education staffâ€”the largest team of art experts anywhere in the worldâ€”research and write the Timeline, which is an invaluable reference and research tool for students, educators, scholars, and anyone interested in the study of art history and related subjects. First launched in 2000, the Timeline now extends from prehistory to the present day. The Timeline will continue to expand in scope and depth, and also reflect the most upâ€“toâ€“date scholarship.
They even offer a tutorial for first time users.