Twenty years ago, the world was stunned by the Asian tsunami, whose towering waves killed an estimated 230,000 people in Indonesia, Sri Lanka, India, Thailand and other countries the day after Christmas.

The tsunami, which was triggered by a powerful 9.3-magnitude earthquake off the coast of northern Indonesia, is considered the deadliest natural disaster this century and one of the deadliest in recorded history.

It wiped out villages, disrupted livelihoods and hit a number of popular tourist…