The World Arch is a term that describes the geography, landscapes and environment of our planet. While there are no true antonyms for this phrase, some words that could be used in contrast to it include "alien worlds," "fantasy realms," and "imaginary lands." These terms suggest a departure from reality, and may be used to indicate a pop cultural reference or a departure from the real world. Other antonyms could include terms such as "underground," "submerged," or "interior," which highlight hidden features of the world that are not immediately visible or accessible. Ultimately, the term "World Arch" represents a broad, expansive idea, and is difficult to find direct antonyms for.