ABC News’ Diane Sawyer interviewed Nemcova in the months after the tragedy. Now, 20 years after one of the deadliest natural disasters in modern history, Petra sat down with Sawyer again to reflect on the horrors of that day, and the kindness of strangers that got her out alive.

Model Petra Nemcova opens up on 'GMA' about surviving the 2004 tsunami that killed 5,000 in Thailand. 'It's always difficult to go back in that moment.'

The supermodel was vacationing in Thailand when a tsunami struck in 2004, killing nearly 230,000 people. Nemcova talks about how the kindness of strangers helped her survive.