Among the wonders of American life that tend to inspire awe in visitors from other countries is the variety of choices available to food shoppers in our supermarkets.

And indeed, our markets are really something, however much we might take them for granted. The bins of glowing fruits and vegetables, glass cases filled with cuts of meat, shelves of canned goods, freezer compartments stocked with every season’s produce and every kind of ready-to-eat fare.

They seem to go on forever – and sometimes almost do: What is possibly the largest supermarket in America, Woodman’s in Kenosha, Wisconsin, covers 252,345 square feet – almost six acres – and even the median supermarket store size around the country is 41,561 square feet. According to the Food Marketing Institute’s compilation of supermarket facts, the average supermarket carries more than 33,000 individual items.

There are almost 40,000 grocery stores in the U.S., more than 26,000 of them categorized as conventional supermarkets, meaning that they stock a full line of groceries, meat, and produce. (Other categories include warehouse stores, natural or gourmet markets, and limited assortment groceries like Aldi.)

While there are independent operators all over the country, the majority of supermarkets belong to chains. Some of these – scores of them – are regional, serving just a single state (like Harmons Grocery in Utah) or even a single city (for instance, Straub’s in St. Louis), while others may cover whole portions of the country, or even operate nationwide.

The largest supermarket chain by far (though of course it carries much more than just groceries) is Walmart, which sold almost $200 billion worth of food and drink in 2016. In second place is the Kroger Company – which operates not just Kroger stores but many other market brands, including Fred Meyer, Harris Teeter, and Ralphs – with more than $110 billion.

Other major players include Albertsons and its brands (Lucky, Pavilions, Safeway, etc.), Ahold Delhaize (Food Lion, Stop & Shop, King Kullen, etc.), Target, and such membership operations as Costco and Sam’s Club. Many of these have a reputation for cleanliness, price, shopper rewards program. These are what many stores use to draw people in – these are America’s most popular stores.