Answer: The Nokia 1100

Hands down, the Nokia 1100 is the most ubiquitous cellphone in the world. From its introduction in 2003 until it was discontinued in 2009, Nokia sold over 250 million of the palm size candy-bar style phones (a record nearly matched by its successor the Nokia 1110). From the streets of India to Nigeria to Chile, the inexpensive, durable, and dependable cellphone brought phone service to hundreds of millions of users.

The phone wasn’t anything to run a cover story about in 2003, and at this point, it’s about as dated as cellphones come, but cutting-edge technology wasn’t the reason it flew off the shelves. The phone was a near perfect match for users in developing countries. It had a terrific battery life (and could be easily charged from a variety of sources like hand cranks and bike-powered dynamos), a membrane keypad that was dust and water resistant, a rubberized body that was light and easy to keep a grip on, and a simple to activate flashlight. Additionally, the embedded software didn’t need updating or any sort of fancy routine maintenance like modern smartphones require.