We are going back to 2400 years ago and our destination is Bthynia Empire capital. It is today’s Bursa county of Turkey.

Bthynia Empire was an important state because it was the neighborhood of East Roman Empire and it was a strong state. They had a net constructed under the city in order to supply water and food during a siege. This net was centered by Bithynia palace. It was so well organized that it could stand against a siege that could last long.

Today we discover those tunnels. It is understood that this net was built by a great engineering even for today.