Today's technology is amazing, but there were some incredible inventions in ancient times that were surprisingly ahead of their time—and some of which continue to impact our lives today. 

Consider the Antikythera mechanism, found in a Greek shipwreck. Dating from 150 BCE, it is the world's oldest analog computer. It could calculate eclipses, trace planetary motion, and even indicate Olympic games—all with gears more sophisticated than anyone thought possible for the era.

Or take Roman concrete. While today's concrete disintegrates in decades, Roman concrete buildings have endured for more than 2,000 years—particularly underwater. Researchers now analyze its distinctive volcanic recipe to design more eco-friendly contemporary buildings.

Even India's ancient stepwells, which were built to conserve water in dry lands, were both beautiful and brilliant. With spiral staircases and deep tanks, they collected rainwater centuries ahead of modern water conservation systems.

These advances serve to remind us that the past is still full of lessons for the future. At times, backward is the way to move forward.