Dualgates
The Dualgates were a gate complex that consisted of two separate stone gates that were placed two miles apart. These gates were located on the main road leading into the underground cities of the Kayolin. They were built partway up parallel valleys and are built out of marble.
These gates protect the easiest route into Kayolin, the valley floors. There was another route that led into Kayolin. This route was the steep trails that continued up into the mountains alongside the valleys. Along these trails was a large communication system that alerted the dwarves of possible intruders that were trying to avoid being seen going through the gates.
The Dualgates could be closed by using the screw and plug system that the Hylar brought with them from Thorbardin when they created the gates. The controls for the gates were located in large rooms underneath the gates. In less then a minute the gates could be sealed.
The Kayolin charged a toll to pass through the gates. They also had visitors meet one of the requirements to be allowed admittance to the underground areas of the kingdom. These gates were the most common entrance for all visitors and merchants traveling into Kayolin.