Prehistoric Art  |  Ancient Art – General  |  Ancient Art – Near East and Egypt
Ancient Art – Greece and Rome  |  Art of the Middle Ages  |  Renaissance and Baroque Art
18TH, 19TH, AND 20TH Century Art  |  Non-European Art  |  Other Interesting Sites

The Seven Wonders of the Ancient World
The history, description, and location of the Great Pyramid of Giza, the Hanging Gardens of Babylon, the Statue of Zeus at Olympia, the Temple of Artemis at Ephesus, the Mausoleum at Halicarnassus, the Colossus of Rhodes, and the Lighthouse of Alexandria.
ce.eng.usf.edu/pharos/wonders/

Mike Gunther's timelines (with links to images) is organized to allow both a synchronic study of history (studying across cultures at approximately the same time, such as the Iron Age in different parts of the world), and a diachronic study of history, examining Egyptian or Greek culture as it develops over time. Another page is devoted to AD/CE.
http://www.art-and-archaeology.com/timelines/tl001.html