Inside the crazy-successful, controversial life of billionaire Uber CEO Travis Kalanick

Eight years ago, Travis Kalanick launched a startup called UberCab in San Francisco.

Now, Uber is a global behemoth and one of Silicon Valley's most successful companies - and one of the most contentious.

Uber operates in nearly 600 cities worldwide, and it's said to be worth nearly $70 billion. The 40-year-old Kalanick is now said to have a net worth of more than $6 billion.

But Uber - and Kalanick - have been caught up in one scandal after another in recent months, calling into question the future of the world's most valuable startup.

Here's how Kalanick got his start and built Uber into a global empire.

Maya Kosoff contributed to an earlier version of this post.