How the Collison brothers built Stripe into Silicon Valley's most valuable startup and became 2 of the youngest billionaires alive

"You're trying to figure out in those early days of starting a company or starting a product, are we wrong or is the world wrong?" John, 30, said on the "How I Built This with Guy Raz" podcast.

The consensus is that they were right beyond measure.

The brothers took their idea for Stripe to Y Combinator, the legendary startup accelerator program in which they had developed their previous startup. And they scored seed funding from marquee investors like Peter Thiel, Andreessen Horowitz and Sequoia.

"They have the advantage of coming to California without being tainted and polluted by what's in the water supply and air of Silicon Valley,"  Moritz, the Sequoia partner, told Bloomberg.