7 insane facts that reveal how big Amazon has become

Amazon is hardly the same company it was in 1999, when e-commerce was still a relatively small industry and the budding online retailer exclusively sold books.

Today, the world's fourth-most valuable company ships a mind-boggling number of goods to billions of people around the world.

By some accounts, it has essentially created America's largest company town in Seattle. Recently, Amazon announced plans to spend $5 billion on a second headquarters, for 50,000 employees, somewhere in North America.

There are a number of ways to look at Amazon's size, and each is just as unfathomable as the last.