Roman concrete still thrives after 2,000 years underwater

Ancient Roman concrete, developed around 150 BCE, endures over 2,000 years in harsh marine environments, unlike modern concrete. This incredible durability comes from volcanic ash, which allowed it to harden underwater and resist degradation. For example, the harbor at Caesarea Maritima, built around 20 BCE, still stands strong despite centuries of waves and earthquakes. Scientists discovered seawater actually triggers a self-healing process in the concrete, forming durable minerals that strengthen it over time. This ancient innovation offers clues for creating eco-friendly modern materials, potentially reducing carbon emissions from cement production.