Minecraft 1.5.2 World File -

The world border isn't infinite here. You eventually find the last explored chunk. Beyond it is a void of ungenerated data.

This is not a "good" world. The builds are ugly by modern standards. The redstone is needlessly complex. The terrain is jagged and harsh. But that’s the point. minecraft 1.5.2 world file

You ride it. For fifteen real minutes, the game stutters as it generates terrain using the 1.5.2 engine. Jungles are laggy in this version. You see the jungle. You keep going. The cart stops exactly at the edge of a ravine. No bridge. No turn. Just… stop. The world border isn't infinite here

Someone built a booster rail system. Not the modern powered rails—the old 1.5.2 kind, where you needed a furnace minecart and a ridiculous loop of golden rails to launch a passenger cart across a continent. This is not a "good" world

Source: 512GB USB drive, unlabeled, found inside a copy of PC Gamer (July 2013)