The game came out in 2002, but up until yesterday, I-am-Prime was still working on fine-tuning an isometric amusement park that was years in the making.
As Prime mentioned in a Reddit post, the park contains 34 roller coasters, 255 attractions and shops, and nearly 8000 guests. To-date, the park's monorail has been ridden by one million different imaginary humans. Also that giant cube-like warehouse in the top left corner is actually an indoor roller coaster.
A zoomed in look at Prime's theme park from late 2015.
In recent years, fans of old-school Rollercoaster Tycoon have been using tools like OpenRCT2 to mod the game,fix bugs, and expanding the game's capacity for bizarre creations. It's how Prime was able to create the above in full HD. And obviously the project used a scenario that didn't take money into account (being a tycoon constrained by capitalism is actually kind of a nightmare).
Prime posted progress on the child-hood project a few years back and you can see how far it's come. The more recent polish is a bit harder to detect unless you look really closely, but such is the nature of polish. The different sections have names as well. "Tron" is the title of the lower right, while "Egypt" and the "Lost Forrest" are located just to the north.
A sequel to RCT2 was released in 2004, but since then the series has languished. A reboot last year called Rollercoaster Tycoon World looked like crap and didn't review much better, leaving it to games like Planet Coaster to pick up the slack and satiate everyone's need to play carnival god.
You can check-out a really gigantic bird's eye view of the park here.