The telephone was invented more than 150 years ago. The history of its invention reads like a detective novel, replete with painstaking work, serendipitous discoveries, moments of enlightenment, and legal battles. Even more intriguing are the events that led to the worldwide adoption of this technology. In this series of columns on IQ.HSE, Anton Basov, HSE Faculty of Computer Science editor, discusses how telephones have become an integral part of our everyday life. The first episode in the series recounts the story of Emperor Pedro II of Brazil demonstrating Bell's telephone at the 1876 Centennial Exposition in Philadelphia.