The Forbes 400 list of the richest Americans was more exclusive this year than ever before. It took $1.7 billion to make the cut, the highest ever in Forbes' history. In comparison, the price of entry was $1.55 billion last year.

Bill Gates headed the pack for the 22nd straight year. And 25 newcomers joined the list, including Snapchat CEO and co-founder Evan Spiegel, who this year became the youngest billionaire in the world. Among the top 20 richest people in America were 10 remarkable entrepreneurs with a collective net worth of $427.8 billion.