(IMAGE) Goethe University Frankfurt Caption Although Caesar had told of comparable obstacles meant to deter the enemy’s approach, so far no physical evidence of their existence had been found. For the most part, the wooden defensive constructions did not survive the test of the centuries. Credit (Photo: Auth) Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.