Svante Pääbo, director of the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology, shares an interesting story in his book Neanderthal Man: In Search of Lost Genomes. Pääbo and his team visited with biotech entrepreneur Jonathan Rothberg at his estate on Long Island Sound. They were hoping to enlist his help in the project to sequence the Neanderthal genome. Pääbo writes that Rothberg had built, on the beach, an exact replica of Stonehenge exact, that is, except that it was made of Norwegian granite and therefore heavier than the original, and it was slightly modified to account for how the sun would fall between the stones on the birthdays of his family members. I found this interesting, not just for the curious fascination some people have with recreating Stonehenge, but for the astronomical alignments Rothberg built into the structure. Some future archaeologist studying this site, without information about the dates of birth of Rothbergs family members, would have no idea that significant astromonical alignments had been encoded into the structure. It made me wonder how many prehistoric sites around the world have alignments that commemorate some culturally significant anniversary that had nothing to do with solstices or equinoxes. Without written accounts, these sorts of alignments would be hard to discover, unless several monuments consistently commemorated the same anniversary, but their significance would be virtually impossible to explain. Brad Lepper