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

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

It destroyed villages, devastated livelihoods and hit a number of popular tourist attractions, killing both locals and visitors from the United States and around the world.

NBC News spoke with three Americans who survived the disaster in Thailand about their experiences.

“Hit by a Mack truck.”

Dr. Libby North, a neurologist from Portland, Oregon, was vacationing with her boyfriend Ben Abels on Ko Phi Phi, a group of islands between Phuket and the Strait of Malacca. On the morning of December 26, 2004, they had gone kayaking and spent some time by the pool before returning to their beachfront bungalow, which was full of travelers.

“Once we got inside, we heard a rumbling noise,” North said. “Then the next moment a wave came through the wall and it felt like I was hit by a Mack truck.”

The north was “washed away at a very high rate.”

Her body was crushed and distorted and she lost consciousness.

“And then the next moment the water receded and I was breathing,” North said.

She was alive but pinned down by rubble. She couldn’t see her arms or legs, and although she could move her left hand, “there was something seriously wrong with my right hand.”

Then another wave came.

Although she wasn’t submerged for long, North said she was pushed further inland and the debris was packed closer around her. Then it happened again with a third wave.

When the waves finally subsided, there was nothing but silence.

“I couldn’t hear another person, which made me think I might be one of the few survivors,” North said.

After a while, she heard some faint voices in the distance and “screamed for my life.” She was rescued by two Thai men who removed the debris. It was discovered that her right hand was “essentially amputated” and that she had severe injuries to her right leg.

They carried her back to her resort, where she was hoisted onto a hovering Thai military helicopter and taken to a hospital in Phuket. There and in Bangkok she underwent multiple operations and although her right hand has limited functionality, it was saved along with her right leg.

Abels did not survive.

“I feared the worst when I didn’t hear him because he was standing right next to me,” North said.

North, who was 34 at the time and very athletic, said she was determined to return to her life and career.

“I play tennis. I ride a mountain bike. I am an enthusiastic skier. I am a mother of three teenagers. I had a wonderful life,” she said.

A divine mistake

Dipak Jain, an adviser to then-Thai Prime Minister Thaksin Shinawatra, had arrived in Phuket the previous evening with his wife and three children.

After breakfast they decided to go to the beach, but took a wrong turn and ended up on the other side of the lagoon. Then they saw the water coming.

“The scene was like Niagara Falls coming at you,” said Jain, a Chicago native.

The wrong turn meant they were out of danger.

It was “a divine blessing that not a drop of water touched the five of us,” said Jain, who is now a marketing professor at the China Europe International Business School in Shanghai.

Jain said it was important for him and others with similar experiences to accept what happened “but be grateful that there are many years ahead of you to share these stories.”

“I always tell people: Forget what you don’t have. Enjoy what you have and make the most of it,” he said. “And share these moments of joy with others in your life.”

‘Then the fear came‘

Chris Xavier, who was vacationing in Phuket with her then-husband, woke up to the sound of water rushing under her door. At first they thought it was a water main breach, but when they went to the beach it was littered with debris.

Dead fish lay scattered all the way to an outdoor restaurant a few hundred feet from shore, and they realized “something had really gone wrong.”

Xavier was in the restaurant with other confused hotel guests when another wave came.

The water threw her against a wall of the restaurant, while her husband was “carried an entire football field away.”

“I was underwater for over a minute to maybe up to two minutes before the water receded enough for me to stand up and breathe air,” Xaver said.

The force of the water pierced tables and chairs into Xaver, leaving a large gash on his head and injuries to his left leg that required 50 stitches.

“Towards the end of that time underwater, I was pretty sure I wasn’t going to make it,” she said.

When she was finally able to stand up, she was the only person there. She managed to find her husband and then someone said that a third wave was coming.

“That’s when the fear came out,” said Xaver. “I knew none of us would survive another wave. We couldn’t run. We couldn’t do that.”

At that moment, a van arrived and took them to a hospital, where they were greeted by a Swedish vacationing doctor, still wearing his swimming trunks. They spent the next three weeks hospitalized in Phuket and Bangkok before returning to the United States on a C-130 military aircraft.

Xaver said her “whole body hurt for months.”

“My whole body, from head to toe, top to bottom, from fingertips to what felt like hair follicles — everything hurt,” she said.

She also struggled with guilt for surviving when so many others had not.

“You really don’t have to blame yourself,” said Xaver. “You really were allowed to survive for a reason.”

Xaver, who recently retired as a college professor in upstate New York, said that after the tsunami she focused less on personal ambitions and more on helping others, including by telling her story.

“I never wish a disaster of this magnitude on anyone, and I certainly don’t wish that many people die,” she said. “But I wish everyone had had a scare in their life, something that would have knocked them out a little bit to say, you know what? This isn’t just about you. There’s more to this world and it’s about love.”