Two works of iron-frame architecture are especially famous. Iron-and-glass architecture culminated with London's Crystal Palace (destroyed), designed by Joseph Paxton (a renowned greenhouse architect) as the main pavilion of the first World's Fair. Some decades later, the foremost iron-frame structure of all time was constructed: the Eiffel Tower, designed by famed bridge engineer Gustave Eiffel.29 The fierce controversy provoked by the tower's plain, unornamented appearance illustrates the era's lack of mainstream acceptance for the "modern look".