Besides its then 3.5-inch touch screen, the first iPhone featured a browser for on-the-go web surfing and built-in apps to check email and get directions.
Phones have gotten so smart that they even talk back to us via helpful digital concierges such as the iPhone's Siri and the recently introduced Assistant on Google's Pixel phone.
The eroding popularity of PCs spurred shake-ups at powerful tech companies such as Microsoft, Intel, Hewlett-Packard and Dell, none of which adapted nimbly to the mobile world unleashed by the iPhone.
Microsoft wound up squandering the $7.6 billion that it spent to buy phone maker Nokia in a futile attempt to catch up to the iPhone.
(Prior to the iPhone's release, Apple posted an annual profit of $2 billion on sales of $19.3 billion.) Its stock-market value is hovering around $635 billion, thanks to a split-adjusted stock price that's risen by nearly a factor of 10 since the iPhone's debut.
Apple suffered its first-ever decline in iPhone sales in its last fiscal year, causing the company to miss its revenue projections and hitting Cook with a 15 percent pay cut .