There are at least 900 other structures of a similar nature that exist in the British Isles alone. At Carnac on the western coast of France are more than 3,000 stone monuments for which astronomical alignments have been claimed.
Newgrange, northwest of Dublin, Ireland, is a Neolithic tomb, part of which was built as early as 3100 BC. It also indicates probable early knowledge of astronomy. The tomb has a long, narrow passage with a slitlike opening that appears to have been designed and engineered to permit the sunlight to enter the burial chamber at the far end momentarily on the morning of the winter solstice.
From architectural studies of ancient Egypt, there is considerable evidence of early, though not prehistoric, astronomical knowledge. The base of the Great Pyramid at Giza is aligned closely with the four points of the compass, and its hidden north passage is aligned with the lower culmination of the North Star at the time the pyramids were built (between 2686 and 2345 BC).
The great temple of Amon, or Amen (Ra), at El Karnak was aligned with the midwinter sunrise during the epoch of Thutmose III (1479-26 BC).
A nearby temple of Khons, the Egyptian moon god, was built to align with the distant hills of Thebes, the northernmost extreme of the setting of the new moon crescent at the time of the summer solstice.
The Dresden Codex, written by the Maya during the 1st millennium of the Christian era, contains astronomical calculations--eclipse-prediction tables, the synodic period of Venus--of exceptional accuracy.
Temples and pyramids in what are now Mexico and Guatemala were often constructed and aligned with attention to astronomical phenomena.
The Plains Indians left stone patterns called medicine (magic) wheels, found along the eastern boundary of the Rocky Mountains from Colorado to Alberta and Saskatchewan.
One of the best known is on top of Medicine Mountain, in the Bighorn Mountains west of Sheridan, Wyo. It is accessible only in the summer, and calculations have been made relating the arrangements of crude sandstone to the sunrise and sunset about the time of the summer solstice and to bright stars that would have been visible at the time archaeologists estimate its construction, about 200 to 400 years ago.
Another medicine wheel, at Moose Mountain in southeastern Saskatchewan, has demonstrably similar relationships but has been estimated as dating from about 2,600 years ago.
A number of stone alignments have also been found in the South Pacific. Such stones on land would, of course, be useless at sea, but it has been suggested that the sites were used for observation and to train voyagers to identify the correct navigational stars before their departure.
The Micronesians and Polynesians used as navigational tools strings of bright stars that rose or set near the same point on the horizon.
The Caroline Islanders had a 32-point star compass for defining this point, using Vega, the Pleiades, and other stars.