The Rollercoaster World started from my idea of linking NPCs together using powered rail.

The spawn point it's at a station where you'll find carts on the rail and all you have to do is to get on board and start.

As you might see in the screenshots there are 2 "parallel" tracks but they're completely different. In case you're going the wrong way, there are certain devices that will put you back onthe right path or kill you,ooopss....
Some might wonder why I did this on a flat world, it's simple: If I builded a rollercoaster on a generated world it would've been too simple, because all I had to do is lay some tracks and set some torches, but on a flat world I had to build everything from zero.

It's full of ups and downs. It will take you about 1h to fully complete. I couldn't even record it because of it's size.