Piedras Bolas (IMAGE) Penn State Caption This is the interior of the Piedras Bolas aqueduct showing the abrupt reduction in conduit size near the exit. Credit Kirk French; Penn State Usage Restrictions Non commercial use only License Licensed 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.