Unique Building - Riverport
Compatibility: BNW required, Hot Seat, Affects Saved Games
Makes the Polder improvement buildable by any civilization and gives the Netherlands the River Port and Estuary Harbour unique buildings.
The Estuary Harbour replaces the Harbour, being slightly cheaper to maintain, and be built not only in coastal cities, but also cities one tile away from the coast provided they have a direct river connection to a workable coastal tile.
The River Port replaces the Seaport, keeping all its features and also granting additional luxuries (like the Arabian Bazaar)
Also makes the Lighthouse (but not the Great Lighthouse) buildable in any city within one tile of a workable coastal tile as well as those cities on the coast.