The two longest distances humans ever had a need to journey were the trips between Strata and the trips between planets.
However, those two were also the shortest trips a human could experience.
It was already known that humans born with spatial abilities were exceedingly rare, but that only meant humanity put more focus into trying to touch upon the concepts of space through technology.
Even researching such technologies drained an egregious amount of money, so they hadn't been developed much at all.
The infrastructure barely existed to create machines capable of controlling space in any capacity, even if it was just a matter of twisting or folding it slightly.
However, nobody else created Strata. Humanity developed the sub-dimensions on its three main worlds on its own, and in the same process, they created ways to move between them.
