Final answer:
Gustave Eiffel helped build the Garabit Viaduct and the interior iron frame of the Statue of Liberty.
Step-by-step explanation:
Gustave Eiffel, a French engineer, is best known for designing the Eiffel Tower in 1889. However, he also helped build several other structures. One notable example is the Garabit Viaduct, a railway bridge located in France, which was completed in 1884. Another significant project is the interior iron frame of the Statue of Liberty, which was designed by Eiffel and completed in 1884.