Gaius S. answered 12/18/21
Latin, Greek, History prof happy to tutor
I do not recall any comments about Stonehenge in Tacitus or Caesar. In general, the Romans saw such things as tourist attractions, but they had more interest in magnificent buildings than old manmade stuff. So they were intrigued by the Seven Wonders of the Ancient World, but less by menhirs. When local tradition told them these objects were religious, the general policy was to leave them alone and not anger some god by moving or desecrating them. This is why many survive today. Much later, in the Middle Ages, Roman cemetaries and deserted towns were scavenged to build housing. Even the Colosseum and the Baths of Caracalla were scavenged to provide building material.