26 incredible innovations that improved the world in 2015

From the start, 2015 was ripe for world-changing innovation.

In early January, we saw Bill Gates drink clean water converted from sewer sludge and human waste by a special processor. In February, social workers and computer scientists came up with an algorithm to prevent the spread of HIV among homeless youth. In March, a research lab created a microchip that could actually help bridge the digital divide in developing countries.

And the revolutionary ideas and inventions tackling the world's most pressing problems kept coming throughout the year. Read more...