Given that the Eiffel Tower is likely the world's best-known iron structure, many other iron constructions have been attributed to its architect, Gustave Eiffel. The Church of Saint Bárbara, in the former copper mining town of Santa Rosalía, contains a plaque near its entrance states that claims it was designed by Eiffel and was rediscovered in a Belgian warehouse after an exposition in 1889 in Paris.

The church has a near-legendary history. It has been said that John D. Rockefeller commissioned the building directly from Eiffel for one of his mines in California. After a series of transport incidents, the ship transporting the building had to be forcefully docked on the Gulf of California and it was reconstructed between 1896-97 after being purchased by the Boleo Mining Company.

Historical records show that the company did operate in the region, but the connections to Rockefeller are unconfirmed. However, it was established by French businessmen, including Charles de la Forgue. It was de la Forgue and his wife who arranged for the shipping of the pre-fabricated building from Belgium to the Baja peninsula. It's believed they were convinced it was the work of Eiffel. In 1993, a United States architecture student, Angela Gardner, studied the building in search of definitive evidence of Eiffel's involvement.

With historical precedents of certified Eiffel works in Latin America, such as the Church of Guayacán in Chile, the claims were not outlandish. However, Gardner's findings were inconclusive, although, its assembly did date to the end of the 19th century.

Further architectural analyses of the church found that it featured elements of Belgian studios known for ironwork, such as Duclos and Danly. With these possibilities, it seems that the true authorship of the design of the Iglesia de Santa Bárbara will remain a mystery.