World's oldest solar observatory?

The current issue of Archaeology [volume 59, number 4, July/August 2006] reports the excavation and reconstruction of a 7,ooo year old circular henge in Germany. Built around 4600 B.C., this wooden henge predates both Stonehenge and the Pyramids of Egypt. Combining GPS and archaeological findings, researchers claim:

". . .the two southern gates of the henge marked the start of the summer and winter solstice, making the enclosure possibly the world's oldest solar observatory."