Viminacium (VIMINACIVM) was a major city (provincial capital) and military camp of the Roman province of Moesia (today's Serbia), and the capital of Moesia Superior. The site is located 12 km (7.5 mi) from the modern town of Kostolac in Eastern Serbia. The city dates back to the 1st century AD, and at its peak it is believed to have had 40,000 inhabitants, making it one of the biggest cities of that time. It lies on the Roman road Via Militaris. Viminacium was devastated by Huns in the 5th century, but was later rebuilt by Justinian. It was completely destroyed with the arrival of Slavs in the 6th century.