The Gateway Arch is the centerpiece of the Jefferson National Expansion Memorial, built on the west bank of the Mississippi at St. Louis, Missouri as a monument to the westward expansion of the United States.

The Gateway Arch’s beginning go way back to the Great Depression and a St. Louis attorney and civic booster named Luther Ely Smith (1873–1951), who intended to make a monument that would restore the city’s riverfront area and inspire tourism (mission accomplished—over 4 million people visit the monument each year). Both the city of St. Louis and the federal government collaborated on building a memorial to the explorers who had pushed the boundaries of the American frontier, including Lewis and Clark (who started their journey in St. Louis), and Thomas Jefferson.

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