Topic summary
Battlements

Extracted from the Wikipedia article Battlement.
History
Battlements are among the oldest known architectural defensive features. The earliest confirmed example is at the Buhen fortress in Egypt, dating to the Middle Kingdom. Battlements also appear on the walls of Assyrian towns, as shown in bas-reliefs from Nimrud and other sites. Traces survive at Mycenae in Greece, and representations on ancient Greek pottery suggest their widespread use. The Great Wall of China incorporates battlements along much of its length.