Ideas take form online. (ArtEd Online).
You might begin an instructional unit by presenting students with an overarching theme or concept and directing them to conduct their own research online, or provide sites you have previously chosen, depending on the age of the students. For example, I have used the following websites as part of a unit on the art and culture of the Middle Ages. Possibilities of focus include cathedrals, castles, stained glass, illuminated manuscripts, tapestries, gargoyles, and unicorns.
New York Carver: Stone Carving, Architecture, Art, and the Middle Ages (virtual tours of cathedrals, abbeys, and castles, gothic geometry, gargoyles, and more)
Gargoyles and Grotesques: Walter S. Arnold, sculptor/stone carver
The Gothic Cathedral and Other Significantly Medieval Sites (lots of photos and illustrations)
History of Art and Architecture: Gothic Art (primarily cathedrals in France)
Cathedral of Our Lady of Angels, Los Angeles, California (recently opened contemporary cathedral, doors by sculptor Robert Graham)
WebMuseum Paris: The Book of Hours/ Les tres Riches Heures du Duc de Berry (twelve-part calendar section from the classic example of a Medieval book of hours)
The Bayeux Tapestry (tapestry based on events surrounding the Battle of Hastings in 1066)
Lady and the Unicorn Tapestries (from the Cluny Museum, Paris)
The Cloisters Collection, Metropolitan Museum of Art (includes The Hunt of the Unicorn tapestries)
Medieval Stained Glass (links to Chartres, Sainte Chappelle, Canterbury, and other cathedrals)
NIXNET Medieval (534 links to sites about the Middle Ages)
Medieval World on the Web (teacher-authored site, includes links to sites made by kids)
Life in the Middle Ages (researched by 4th and 5th grade students)
Castles on the Web (links, information, images)