While most parents are well into the nesting phase once their newborn arrives, new father Elon Musk is instead selling a pair of Bel-Air mansions along with the rest of his physical possessions. The Tesla and SpaceX CEO has listed two of his seven homes after promising to "own no house" on Twitter. Located on the same street, the first property is a $30 million estate that includes 16,250-square-feet of living space with seven bedrooms, a two-story library, wine cellar, pool, and a championship tennis court while the other is the former residence of actor Gene Wilder. The latter, listed for $9.5 million, comes with a stipulation: the home cannot be torn down or lose any of its soul. But don't lose any sleep over the billionaire's finances. Musk also tweeted "Don't need the cash. Devoting myself to Mars and Earth. Possession just weigh you down."