Archaeologists in Croatia have unearthed the remains of a 1,800-year-old watchtower that was erected to help the Romans defend the "limes" -- the border along the Danube River that marked the frontier of the Roman Empire.Roman artifacts revealed at the site, including military equipment, brooches and ceramic vessels, indicate that the watchtower was constructed in the late second century A.D. and used in the third century A.D., the team reported...During the Marcomannic Wars (circa A.D. 166 to 180), Roman soldiers under the rule of emperor Marcus Aurelius fought several peoples -- including the Germanic Marcomanni who lived north of the...