The Eiffel Tower, built especially for the Exposition, was the tallest structure in the world at the time. A competition to build what was simply called "A tower of three hundred meters" with a base one hundred meters wide, was announced in 1886. It was won by the construction firm of Gustave Eiffel, which had recently built the iron frame of the Statue of Liberty. The Eiffel firm had advance knowledge of the project and, beginning in 1884, had already designed a tower exactly to those dimensions. The structural design was created by two Eiffel engineers, Maurice Koechlin and Émile Nouguier, who along with Eiffel himself, received the patent for the plan. An Eiffel architect, Stephen Sauvestre, designed the curving form and decoration which gave the tower its distinctive appearance. Eiffel was granted exclusive rights for twenty years to operate the tower and its restaurants and viewing platforms. A site next to the River was chosen, despite the infiltration of river water, since that land was owned by the City of Paris, and the tower could be kept in place after the Exposition was completed.