While some business owners proudly take the title of scrappy entrepreneur in earning their fortunes, others are simply born into wealth.The number of dynasties holding much of the wealth in the world may be slowly shrinking, but a fair number of relatives still hold a place as billionaires on Forbes’ list of wealthiest individuals. When it comes to the wealthy, there are some family empires that are the cream of the crop. Together, the top five wealthiest families in the world, all from the U.S., have a combined net worth of more than $232 billion. That’s a lot of cash for only five sets of relatives.Here are the five richest family empires in the world, according to the Forbes 400.1. The Waltons’No, these aren’t characters from the beloved 1970s television series. This is the family of brothers Sam and James Walton, the men who founded WalMart back in 1962. As the retailer has expanded its global reach over the years, so too has the family wealth. The international discount retailer brought in revenues of $405 billion in 2010, and has helped the family achieve a combined net worth of $93 billion.2. The Koch’sWhile this name may not be as familiar, you should get to know this wealthy trio. This family of three brothers claim the majority stakes in Koch Industries (around $100 billion in shares), which runs pipelines, creates fertilizer and owns forestry giant Georgia Pacific. And all that industry has the Koch brothers slotted firmly in the second spot for the wealthiest family empire. The siblings have a combined net worth of $54 billion.3. The Mars’The wealth of the Mars family proves that making a fortune can be a sweet journey. Three siblings share ownership of the world’s largest confectionary company, which produces the famous chocolate by their name, Mars Bar, along with M&Ms, 3 Musketeers, Milky Ways and a laundry list of other beloved sweets. The company brought in whopping revenues of just under $32 billion in 2010, giving the family a combined net worth of $41.4 billion.4. The Cox’sThis family has turned the art of communication into a very successful moneymaking enterprise. The Cox family shares ownership of Cox Enterprises, which is comprised of a number of television, newspaper and radio brands, including Cox Media and Cox Communications. The founder’s grandson, Jim Kennedy, is the chairman of Cox Enterprises, which helped the family reach a combined net worth of $24 billion. Three of the relatives in the family have made it onto the Forbes 400 list.5. The Pritzker’sWith a combined net worth of $19.6 billion, this family of 11 relatives inherited the mother load of industrial assets. The industrial holdings were originally established by A.N. Pritzker with sons Jay and Robert. But the family is also known for running the Hyatt hotel chain and for several other well-known assets, such as the TransUnion credit bureau, the Royal Caribbean cruise line and the Superior Bank of Chicago.