The milestone gave the company a market capitalization of more than $477 billion. Shares closed at $996.70.
Since 1994 when Amazon was founded, the online retailer has expanded to sell electronics, clothing and accessories, food and more. It is now the world's largest provider of cloud infrastructure services, which is likely to help fuel its growth for the foreseeable future. In 2015, Amazon surpassed Walmart (WMT) - Get Report as the most valuable retailer in the United States by market capitalization.
Here are some other noteworthy moments in Amazon's history.