Banda Aceh. People gathered in prayer and visited mass graves Thursday in Indonesia's Aceh province to commemorate 20 years since the Indian Ocean tsunami, one of the deadliest natural disasters in modern history.

In Ulee Lheue village, where more than 14,000 unidentified and unclaimed victims are buried, mourners openly wept. This site is one of several mass graves in Banda Aceh, the capital of Indonesia's northernmost province, which was among the areas hardest hit by the disaster.

On Dec. 26, 2004, a powerful 9.1-magnitude earthquake struck off the coast of Sumatra, triggering a tsunami that killed an estimated 230,000 people across a dozen countries. The waves reached as far as East Africa and displaced 1.7 million people, mostly in the four worst-affected nations: Indonesia, Sri Lanka, India, and Thailand.

Indonesia bore the brunt of the disaster, with more than 170,000 lives lost. Survivors still grapple with the memory of the towering waves that devastated Aceh’s coastline, leaving flattened buildings and unthinkable grief in their wake.

Today, Aceh's infrastructure has been rebuilt and is more resilient. Coastal communities are equipped with early warning systems, providing residents with critical time to evacuate during potential tsunamis.

The recovery was made possible by international donors and organizations, whose contributions helped rebuild schools, hospitals, and essential infrastructure. These structures have been reconstructed with improved strength and durability, better preparing the region for future challenges.

Thailand also suffered immense loss, with over 8,000 people killed, many of whom remain missing. Nearly 400 bodies remain unidentified, underscoring the profound emotional scars the tsunami left behind.

Even two decades later, the pain of that day lingers, as communities across the affected regions continue to honor the memories of their lost loved ones while striving to build a safer and more prepared future.