|Build cost||Stone x4 per unit of length|
The Tunnel is a simple way of Labourers getting though mountains. The cost of the Tunnel will get more expensive the longer it gets, so it will end up cheaper if built though thinner areas of the mountain. The Tunnel can be built in horizontal and vertical lines, but not diagonals. A Tunnel must maintain its straight shape though the mountain, so it cannot adopt a zigzag style like roads. There is currently only a Stone version of the tunnel, meaning it has no upgrades, nor a cheaper version.