On the Eiffel Tower, seventy-two names of French scientists, engineers, and mathematicians are engraved in recognition of their contributions. Gustave Eiffel chose this "invocation of science" because of his concern over the protests against the tower. The engravings are found on the sides of the tower under the first balcony. The engraving was painted over at the beginning of the twentieth century and restored in 1986–1987 by Société Nouvelle d'exploitation de la Tour Eiffel, a company contracted to operate business related to the Tower. The Tower is owned by the city of Paris. The letters were originally painted in gold and are about 60 cm high. The repainting of 2010/2011 restored the letters to their original gold colour.