Chicago

In 1900, Chicago got so tired of its sewage flowing into its drinking water that it reversed the direction of an entire river. Engineers dug a massive canal and forced the Chicago River to flow backward, away from Lake Michigan and toward the Mississippi.

It still flows the wrong way today.

That kind of brute-force engineering defines Chicago. The city had already rebuilt itself once from almost nothing.

On October 8, 1871, a fire broke out near a barn on the city's southwest side. It burned for nearly two days, destroyed around 17,500 buildings, and left roughly 100,000 people homeless.

Most of the city was made of wood and never stood a chance.

Chicago rebuilt almost immediately, and this time it built up. In 1884, architect William Le Baron Jenney finished the Home Insurance Building, a 10-story tower held up by a steel frame instead of thick stone walls.

It was the world's first skyscraper, and it changed how cities everywhere would look.

By 1890, Chicago was the second-largest city in America. Three years later it hosted the 1893 World's Columbian Exposition, a fair so enormous that 27.5 million people visited, close to half the U.S. population at the time.

The fair introduced the world's first Ferris wheel, built by George Ferris as America's answer to the Eiffel Tower. It stood 80 meters tall and carried 1.4 million riders.

Ride to the 103rd floor of the Willis Tower and step onto the Skydeck's glass ledge, which juts out over the street far below. Walk through Millennium Park to find Cloud Gate, the giant mirrored sculpture everyone calls "The Bean."

Take an architecture boat tour along the river to see the skyscrapers from the water. Meet SUE, one of the most complete Tyrannosaurus rex skeletons ever found, at the Field Museum.

Eat a deep-dish pizza, the knife-and-fork pizza with a crust like a pie and cheese under the sauce, said to have been invented at Pizzeria Uno in 1943. Grab a Chicago-style hot dog loaded with mustard, relish, onions, tomato, pickle, and peppers, but never ketchup, which locals treat as a minor crime.