The Portal is an enormous energy doorway that allows practical, rapid travel between two distant locations, which appeared in the film Treasure Planet. It is possible the portal was also built by the ancient alien race that created Treasure Planet.
The Map that led to Treasure Planet also worked as the portal's control panel once plugged into a certain keyhole and would project an orbital list of locations. One touch on one of the projected destinations and the portal would instantly open a doorway to that destination, large enough for a ship to pass through.
Captain Nathaniel Flint was known to use this portal to roam the universe, stealing treasure and would stash it at the center of Treasure Planet. After Flint passed away, the Map was somehow recovered by Billy Bones and upon arriving at Treasure Planet, Jim activated the portal after figuring out the keyhole in the ground. Using the portal they were able to enter the center of the planet where they found it piled with miles of treasure. Unfortunately, when they set off Flint's bobby trap, causing the planet's cataclysmic destruction. Jim, Silver and Morph return to the surface through the portal before being picked up by the R.L.S. Legacy. Consequently, the ship sustained damage to its engines, making it impossible to escape the planet's destruction. Luckily, Jim had the Legacy turn back towards the portal, changing its destination to Crescentia spaceport, narrowly escaping the destruction of Treasure Planet in the process.