Minecraft Story Mode:Portal Network

The portal network, refered to as a hallway by the protagonists, is a location created by Old Builders that serves as a hub for portals into different worlds.

Layout
Portals in the portal network have different colors. Each portal has a "frame" made out of a material that represents the world this portal leads to. One wall contains a secret quartz staircase that leads to Old Builders if the redstone heart is placed inside of it.

Usage
The portal network was used by the Old Builders to travel between worlds. They've created an atlas to help them navigate between the worlds.