Once every decade or so comes an innovation so transformative that it changes the game in its field, becoming the technology to build on for the next decade’s breakthrough. Arpanet, the U.S. Department of Defense project to link computers of disparate types was that breakthrough for the 1960s; it laid the foundations of the Internet. The following decade brought the first cellular phone. The personal computer took hold in the 1980s. The first Web browser came in the 1990s. And in 2007 came the device that brought it all together: the Apple iPhone.

The technologies behind the iPhone existed before Apple engineers integrated them. The true breakthrough was what this slim, glass and aluminum slab enabled: always-on connectivity. These days, we can take for granted the ability to conduct business and interact with our friends anywhere, any time, but it was this one device—in tandem with a robust cellular network—that launched the connected revolution.