Classical

Wikipedia Classical Architecture - An illustrated history and description of the architecture of ancient Greece and Rome.
http://en.wikipedia.org/wiki/Classical_architecture

Kusadasi.biz: Ephesus Guide - A tour of the astonishing remains of a Greek and later Roman town in Turkey, including history and interactive panoramas.
http://www.kusadasi.biz/ephesus.asp

Classical Orders of Architecture - An illustrated description of the Doric, Ionic and Corinthian orders from the Charlotte-Mecklenburg Historic Landmarks Commission.
http://www.cmhpf.org/kids/dictionary/ClassicalOrders.html

Maecenas: Images of Ancient Greece and Rome - Photographs by Leo Curran, University of Buffalo, of Classical remains across Europe, with some models and reconstructions of their original appearance. Searchable.
http://wings.buffalo.edu/AandL/Maecenas/index.html

The Museum of Reconstructions - A non-profit digital museum creating electronic reconstructions of ruined masterpieces of ancient architecture.
http://www.reconstructions.org/