The Billionaire’s Belt in midtown Manhattan isn’t the only place where the .01 percent are spending mounds of money on real estate. The Hilton-Hyland realty blog, run by Bilal Khan, formerly of Curbed, today spotlights a Billionaire’s Hill in Bel Air, one of the neighborhoods featured in Unreal Estate. Want to rub garden hoses with Elon Musk (pictured)? He’s today’s king of the hill.