At its peak, Forever 21 made $4.4 billion in revenue. Here's what led to the brand's downfall and bankruptcy.

At its peak, Forever 21 made $4.4 billion in revenue and was one of the fastest-growing fast fashion empires. Now, the retailer is preparing to file for bankruptcy after alienating its core customers and struggling to keep up with the rise of e-commerce. As one of the largest tenants of American malls, a large-scale shutdown of Forever 21's stores could exacerbate the ongoing retail apocalypse.