alphadogg writes These days, making a call across the U.S. is so easy that people often don't even know they're talking coast to coast. But 100 years ago Sunday, it took a hackathon, a new technology and an international exposition to make it happen. The first commercial transcontinental phone line opened on Jan. 25, 1915, with a call from New York to the site of San Francisco's Panama-Pacific International Exposition. Alexander Graham Bell made the call to his assistant, Thomas Watson. Just 39 years earlier, Bell had talked to Watson on the first ever phone call, in Boston, just after Bell had patented the telephone.