Kansas, Nebraska, North Dakota, South Dakota, Oklahoma, and Iowa sit at the heart of the Great Plains, a vast stretch of flat to gently rolling terrain that has made this region the country's agricultural core.

Wheat, corn, and soybeans dominate the landscape, and the Ogallala Aquifer — one of the largest groundwater reserves in the world — runs beneath much of the region, supplying the irrigation that keeps its farms productive.

The wide-open, steady winds that once defined the Plains as farm country have also made it a leader in wind energy: Iowa and Kansas both rank among the top states in the country for wind power generation.

Outside of cities like Omaha, Wichita, Des Moines, and Oklahoma City, the Plains states remain some of the least densely populated in the country, a sharp contrast to the crowded coasts.

This quiz tests capitals and abbreviations across a region that quietly produces much of the country's food supply.

Not all of the Plains is flat, though — South Dakota's Black Hills are home to Mount Rushmore, a granite outcrop carved with the faces of four presidents, breaking sharply from the surrounding prairie. The region also overlaps heavily with 'Tornado Alley,' the corridor that sees some of the highest tornado frequency in the world, especially across Kansas, Oklahoma, and Nebraska. In the 1930s, this same region endured the Dust Bowl, when drought and poor farming practices stripped topsoil and forced hundreds of thousands of families to migrate west.

Iowa alone produces more corn than most countries in the world, and the state's flat, fertile terrain is largely a legacy of glaciers that flattened the land thousands of years ago and left behind rich topsoil.