via <a href='https://images.indianahistory.org/digital/collection/dc012/id/14821/rec/11'>Bass Photo Co Collection, Indiana Historical Society</a>. Image Edificio de Indiana Bell en proceso de rotación.
In November 1930, in Indiana, United States, one of the great feats of modern engineering was executed: a team of architects and engineers moved an 11,000-ton (22-million pound) telephone exchange without ever suspending its operations either basic supplies for the 600 employees who worked inside.