See what it's like inside Amazon's massive warehouses

Robert Galbraith / REUTERS

Tis the season for holiday shopping.

Starting with Black Friday and Cyber Monday and then spanning several more weeks of last-minute holiday shopping, it's the most lucrative time of year for online retailers like Amazon.

Amazon can only keep up with the demand because of the efficiency of its more than 50 fulfillment and 20 sortation centers across the US.

Take a peek inside:

Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.