Rainbow. A literally enormous rainb...

Rainbow. A literally enormous rainbow-shaped structure, primarily using glass, glowstone, sea lanterns, and other similar blocks. I need a truly enormous rainbow-shaped structure to impress the viewer. Also, at the very bottom of this rainbow should be a bunker, inside of which there will be a long obsidian labyrinth, crammed with various rooms reminiscent of a large clan's hiding place. Something like a warehouse, a church, mines, and so on, but all mysteriously located underground.