you can build many type of blimps that near the port i can be a air port for planes o blimps like the hinderburg :3

A legit shipping harbor like in Miami or New York

what about a dry dock with some ships in them

you can build the golden gate bridge and you can give a new name like the golden harbor bridge

How about a shipyard with uncompleted ships in drydocks undergoing construction. I personally think it's a great idea, however I do not know if it is too complicated to be an actual concept.

perhaps working floating docks or drydocks that fits the microscale ships

A power plant or something or some kind of industry

maybe you can build the chernobyl

Gonna quickly say this, thank ya'll for the ideas! Several of these seem really good and I hope to gettem in. A response to a few:
Blimp port/airport: I hope to include these, most likely going to be in the swampy area due to the flat land.
Drydock/Drydock shipyard: This seem like a really good idea, and I think a shipyard showing off work-in-progress ships would be really neat! As for a drydock itself.. I wanted to see if a lock would somehow work too.
Coastguard: This would really fit the theme good.
Other industries are going to be coming, along with villages/towns.

howdy i think a mini railway might be interesting as you can make it function with sliders also mauve what scale do you build your ships in ive tryed a few but they dont fit with the rest of the build

@Happy snacks I dont really have a proper scale, but each of the ship doors are 1.5 blocks. I normally just base it off of that

ok thank you

howdy i think a international airport in the big city would add some nice detailing

what about a nuclear power plant, or maybe large towers, maybe base some of it off of dubai?

Maybe you could make a military base somewhere