The Universal Exposition of 1878, which lasted from 1 May to 10 November 1878, was designed to advertise the recovery of France from the 1870 Franco-German War and the destruction of the period of the Paris Commune. It took place on both sides of the Seine, in the Champ de Mars and the heights of Trocadéro, where the first Palais du Trocadéro was built. Many of the buildings were made of new inexpensive material called staff, which was composed of jute fiber, plaster of Paris, and cement. The main exposition hall was an enormous rectangular structure, the Palace of Machines, where the Eiffel Tower is located today. Inside, Alexander Graham Bell displayed his new telephone and Thomas Edison presented his phonograph. The head of the newly finished Statue of Liberty ("Liberty Enlightening the World") was displayed before it was sent to New York City to be attached to the body. Important congresses and conferences took place on the margins of the exposition, including the first congress on intellectual property, led by Victor Hugo, whose proposals led eventually to the first copyright laws, and a conference on education for the blind, which led to the adoption of the Braille system of reading for the blind. The exposition attracted thirteen million visitors, and was a financial success.