Seven years ago, the four brothers behind the Hinduja Group, a multi-billion dollar transnational conglomerate, laid down $95M for a quartet of combined London townhouses designed in the 19th century by architect John Nash. Sure, they were already living in a 25,000-square-foot mansion across the street, but this opportunity presented the chance to own "something grander," according to a recent Forbes piece. After all, what's two across-the-street mansions for guys worth $8B? After investing another $95M into restoring and renovating the building—"nearly gutting it to its bare brickwork in several places" and hiring up to 140 people, at one point—the 67,000-square-foot palace was finished two years ago, and now plays host to a rotating stable of frolicking billionaire guests. Inside: Greco-Moorish ceilings, a half-ton Murano-glass chandelier, six formal sitting rooms, 25 bedrooms, a "leisure zone," and a "Gold Room" with a gold-leafed ceiling. Taking into account the mansion listed for almost $400M down the block, someone from the London consultancy Knight Frank appraised the home at $500M. So yes, this is "something grander," for sure, yet the Hinduja brothers haven't actually moved: they still live across the street.