Last year, shoppers spent $7.9 billion on Thanksgiving Day and Black Friday. An additional $6.59 billion was dropped on Cyber Monday. This year, Black Friday sales alone are expected to jump to $9.1 billion. And one retailer dominates these sales: Amazon. Last year, Amazon accounted for 45 percent of all Thanksgiving Day online purchases and 60 percent of purchases on Black Friday, according to Hitwise. The Seattle e-commerce giant is expecting similar numbers this year, and has been making an even more aggressive push, offering free shipping to all shoppers during the holiday season, with no minimum purchase. While this may be great for Amazon’s bottom line, all this shopping has a real human cost. As plenty of Amazon employees have attested, working in the company’s warehouses is grueling. Read more at Vox.