gardens considered one of the Seven Wonders of the World and thought to be located near the royal palace in Babylon. By the beginning of the 21st century, the site of the Hanging Gardens had not yet been conclusively established; nevertheless, many theories persisted regarding the structure and location of the gardens. Some researchers proposed that these were rooftop gardens. Another theory, popularized by the writings of British archaeologist Sir Leonard Woolley, suggested that the gardens were built within the walls of the royal palace at Babylon, the capital of Babylonia (now in southern Iraq), and did not actually "hang" but were instead "up in the air"; that is, they were roof gardens laid out on a series of ziggurat terraces that were irrigated by pumps from the Euphrates River. Traditionally, they were thought to be the work either of the semilegendary Queen Sammu-ramat (Greek Semiramis, mother of the Assyrian king Adad-nirari III, who reigned from 810 to 783 BC) or of King Nebuchadrezzar II (reigned c. 605-c. 561 BC), who built them to console his Median wife, Amytis, because she missed the mountains and greenery of her homeland.