January 17, 1995, 05:46. This was the moment 20 years ago that the Great Hanshin-Awaji Earthquake struck and resulted in 6,434 lost lives, 200,000 destroyed buildings, 300,000 people made homeless, and a staggering economic cost then calculated at 2.5 percent of Japan's GDP (approximately $100 billion).

As for all disasters, the human toll, including the psycho-social impact on survivors, is the greatest tragedy. It reminded us of the constant need for communities, cities, and nations to enhance prevention and preparedness, to ensure that response systems are efficient, and that communities build their resilience to withstand and cope with any future disaster.

The Great Hanshin-Awaji Earthquake ushered in a new era of volunteerism in Japan, and highlighted many lessons on how to prepare for disasters arising from hazards of all kinds, improve care and support for the survivors, as well as to rebuild cities and their health systems. The 2011 Great East Japan Earthquake, and so many other natural disasters in the past two decades across the world, illustrated the need to continuously apply past lessons.