The Missouri History Museum occupies a Beaux-Arts building at the north end of Forest Park, built in 1913 as a memorial to Thomas Jefferson and funded entirely by surplus from the 1904 World's Fair. The permanent collection covers the history of St Louis and Missouri — the Lewis and Clark expedition, the World's Fair itself, the city's industrial peak, and the civil-rights history of north St Louis.
The 1904 World's Fair gallery is the standout: it brings together what is left of the Louisiana Purchase Exposition, the world fair that drew nearly 20 million visitors and reshaped this part of the city. Free admission; allow about two hours.