Age of Empires got me into tinkering with content generation. The flexible map rules were fantastic in making this possible.
Minecraft is of course the poster child for very large worlds of interest these days.
Dwarf Fortress crafts an entire continent complete with a multi-century history, the results of which you can explore freely in adventure mode.
Most of the recent examples of 3D worlds like the post tend to do it through wave function collapse.
> Minecraft is of course the poster child for very large worlds of interest these days.
Minecraft used to create very interesting worlds until they changed the algorithm and the landscapes became plain and boring. It took them about 10 year until the Caves and Cliffs Update to make the world generation interesting again.