North Dakota and South Dakota are the two smallest, least-covered states in the country by nearly every measure this site tracks. They are also sitting on a sovereign wealth fund modeled after Norway's and the largest concentration of trust assets in the United States -- neither one an accident, both one legislative act away from never existing.

South Dakota holds more than $900 billion in trust assets -- more than the GDP of most countries -- because state law lets a trust run forever, with a level of secrecy Delaware and Nevada can't match. Almost nobody outside the trust industry knows this is where it happens.

Fifty years of Landsat -- the satellite program that has photographed every square mile of Earth's land surface, repeatedly, since 1972 -- has one physical home. It isn't in Washington, or Houston, or anywhere you'd guess. It's in Sioux Falls, South Dakota, the same city that processes a huge share of the country's credit card transactions.

A mile underground, in a hole dug for gold, sits one of the most sensitive physics experiments on Earth -- and the largest neutrino experiment ever built anywhere is currently being carved into the rock beside it, fed by a particle beam shot 800 miles through the ground from a lab in Illinois.

In February 1980, a broke state and a bank losing money on credit cards made a secret deal. South Dakota repealed its own interest-rate caps. Citibank moved its credit card operation to Sioux Falls. The Supreme Court later let every national bank do the same thing, anywhere, using whichever state's law was most favorable to it. Almost every American's credit card statement still traces back to that one 1980 decision.