The Chicago River reverses its flow. Engineers redirected the waterway in 1900 to spare Lake Michigan from industrial waste, and the channel that once fed the city became its sewage conduit south toward the Mississippi. A century later, the river carries a different cargo: ninety-minute architecture sailings that glide beneath bridges named for Wabash, LaSalle, and Wells, past glass towers that replaced the timber yards and grain elevators of the Gilded Age. The chicago river cruise architecture tour departs from 112 East Wacker Drive, where the south bank curves toward Michigan Avenue and the Wrigley Building's terracotta clock towers still catch morning light. Chicago built the modern skyscraper here. William Le Baron Jenney's Home Insurance Building rose ten stories in 1885, the first to carry its weight on an iron frame rather than masonry walls. Louis Sullivan clad steel in ornament; his Carson Pirie Scott store at State and Madison wrapped a grid in cast-iron foliage. Daniel Burnham gave the city its Beaux-Arts grandeur—Union Station, the Rookery's light court, the Plan of 1909 that reserved the lakefront for public use. The 1922 Chicago Tribune Tower stands at 435 North Michigan, a Gothic Revival crown chosen by competition, its base studded with fragments from the Parthenon, the Taj Mahal, and the Great Pyramid. The postwar generation turned to glass. Mies van der Rohe's 860-880 Lake Shore Drive apartments opened in 1951, twin black slabs on the waterfront. The Inland Steel Building introduced column-free office floors in 1958, pushing structure to the perimeter. Skidmore, Owings & Merrill designed the John Hancock Center and Willis Tower, both engineered by Fazlur Rahman Khan, who invented the bundled tube that let Chicago rise above one hundred stories. The river's architecture sailings pass all three—Marina City's corncob towers, the reflective glass of 333 West Wacker, the limestone piers of the Michigan Avenue Bridge. Docents narrate from the open deck, tracing the grid from the 1871 fire to the 2020s, when the riverwalk added kayak launches and the city dyed the water green each March. The chicago river cruise architecture tour runs daily, boarding fifteen minutes before departure, returning to the same dock after ninety minutes upstream and back.