Warner Bros. and Legendary Entertainment's MonsterVerse is building towards an epic clash in 2020's Godzilla vs. Kong, but so far the films in this shared universe have largely stood on their own, with Kong: Skull Island taking place decades before Godzilla. The only major ties between them are Monarch and Skull Island's end credits scene. Yet Godzilla: King of the Monsters appears to be plotting an important connection to Kong: Skull Island; one that ties the universe together while explaining how the Titans remain hidden for so long. It all goes back to William Randa's Hollow Earth theory.
As a refresher, in Kong: Skull Island, John Goodman's character, the senior Monarch operative Bill Randa, postulated that beneath the surface of the Earth, there are gigantic underground caverns inhabited by M.U.T.Os: Massive Unidentified Terrestrial Organisms, or Titans as they are also called. According to Randa, Skull Island was one of the places on the planet where these caverns exit above ground, thus explaining the island's wildlife. Now, what does all of that have to do with Godzilla: King of the Monsters? Well, the film's viral marketing site, MonarchSciences.com, seems to confirm Bill Randa's Hollow Earth theory from Kong: Skull Island.
The viral site allows fans to assist Monarch in tracking Godzilla and any other Titans across the planet in real-time, as a means of preparedness after the events of the 2014 film. Godzilla appeared in San Diego back in July, just in time for Comic-Con where he had a hot new trailer to drop. After that he headed back out to sea, swimming west across the Pacific and passing Skull Island along the way, until he reached the Mariana Trench and vanished. How does something that big go missing and how did he stay hidden in the first place? Presumably he dove down into the Mariana Trench, which is the deepest known point on the planet. It would have been easy to think that his home was at the bottom of the trench and he went back into hibernation, if not for the fact that Godzilla eventually emerged thousands of miles away, west of Indonesia.
Unless Godzilla has added teleportation to his list of skills alongside atomic breath, the only explanation for him disappearing and reappearing like that is he entered one of Bill Randa's hypothesized caverns at the bottom of the Mariana Trench and then moved through the caverns under Indonesia to an exit on another spot on the planet. This basically confirms the theory put forth by John Goodman's character in Kong: Skull Island while expanding on the mythology, showing that the island from that film is not the only gateway into the Hollow Earth. This is exciting for the MonsterVerse mythology, as it establishes how the Titans have remained hidden for so long while also providing a new, dangerous element considering that we don't know where all of the cavern entrances lie. Perhaps some could even be under cities.
Also of note is that after he popped up in the Indian Ocean, Godzilla hooked a left, and there's only one thing in that direction: Antarctica. Judging from the trailer for Godzilla 2, King Ghidorah is hidden in a block of ice down there, so maybe Godzilla senses that his foe is about to be freed and he wants to be there to greet him.