The Eiffel Tower is the undisputed icon of Paris, but when Gustave Eiffel designed it, he reserved a very special secret space at the top. What is it?

The Taj Mahal is famous for its near-perfect symmetry in white marble. However, there is a single element within the complex that intentionally breaks that harmony. What is it?

The Statue of Liberty illuminates New York Harbor, but it did not always feature its signature blue-green color. What color was it originally?