Unique Improvements
Mountain Tunnel
Description
Unlocks the Military Engineer ability to construct a Mountain Tunnel.

Acts as a movement portal on a mountain range, allowing units to move into it and exit from another portal at the cost of 2 [ICON_MOVEMENT] Movement. Multiplier of [ICON_GOLD] Gold yield from districts at their destination [ICON_TRADEROUTE] Trade Routes passing through Mountain Tunnel is set to +100% (max. +100%). Can only be built on an adjacent Mountain tile. Cannot be pillaged or removed.
Requirements
Technology
Built By
Language