In order to understand the ins and outs of owning and maintaining some of the most ridiculously expensive homes money can buy, you need to look inside the homes and buying habits of the worlds richest people: Billionaires who buy beachfront mansions by the dozen (Oracle CEO Larry Ellison); Junk Bond kings with 39 bathroom mansions (Ira Rennert); and the overlord of a household staff numbering 600 workers (Indian tycoon Mukesh Ambani). It's The Filthy Rich Guide to the biggest, most luxurious homes on land or sea.