OK let me actually put some thought into this. I'm going to try not to make it sort of balanced. It won't be as good at polding as the dutch are, or as good at mountains as the inca are, but a bit of both. It's kind of funny to put the notoriously flat netherlands with the mountain civ, but I love both their tile improvements! I'll come up with proper names for these things later. Leader ability: Domestic trade routes provide +1 food for every mountain in the origin city and +1 production for every lake or oasis tile adjacent to a mountain in the origin city. Cities that have a trade route passing through a mountain via a terrace polder recieve +2 loyalty. Civ ability: Lake and coast tiles next to mountains gain +1 faith and +1 food. Districts gain +2 adjacency if they are adjacent to both a mountain and a fresh water source (lake, oasis, river, some natural wonders). Recon units can disembark and embark without using any movement points. Can build canals on hill and canals are unlocked at construction. Unique unit: Replaces quadrireme. Can shoot twice like the Incan unique unit and also has +1 move. +1 range but only when on lake. Costs 30% more hammers to build. Unique improvement: Terraced polder. Unlocked at irrigation. Can be built in any lake tile or oasis tile (I know you can't usually put things on oasis tiles!). Can only be built if the tile is next to at least two hills, or at least two mountains, or at least one of each. +2 gold, +1 production and +1 food. Gains +1 faith for every adjacency mountain. Gives +1 food for every adjacency terrace polder. +2 culture on conservation. If city doesn't have fresh water, provides fresh water, like an aqueduct. Allows units to go through adjacent mountains, like the mountain tunnel. So... the city has ended up being focused on mountainous lakes. I guess it's... switzerland?