What’s the scariest thing that’s ever happened to you? What’s the most dangerous thing you’ve ever done?

Retired Canadian astronaut Chris Hadfield took the stage this week at the annual TED Conference in Vancouver and talked about the scariest thing that’s ever happened to him: going blind during a spacewalk.

“Suddenly my left eye slammed shut and (there was) great pain and I couldn’t figure out why my eye wasn’t working,” he said. “I was thinking: what do I do next?”

But by “looking at the different between actual danger and perceived danger,” Hadfield was able to overcome his fear and work through the problem despite being completely blind outside his spaceship.

“It would be impossible to go outside on a spacewalk or even pilot a rocket ship if you didn’t prepare for it somehow,” he told CTV Vancouver on Wednesday.

“You sort of have to exaggerate yourself a little bit in order to figure out how to conquer the fear in something as dangerous and visceral as that.”

So how did Hadfield compare to previous TED talk speakers?

Keep reading to find out about the five most-viewed TED Talks of all time.

Ken Robinson: How schools kill creativity

In the most-watched video of them all, creativity expert Ken Robinson says children are being educated “out of their creative capacities” through systems that stigmatize mistakes.

It doesn’t matter where you go in the world -- mathematics and languages are at the top of the hierarchy, Robinson says. Then, at the bottom, you find humanities, and finally, the arts.

Robinson asks: why isn’t music, drama, art and dance given a higher status in the school system?

Amy Cuddy: Your body language shapes who you are

Harvard Business School professor Amy Cuddy says body language does more than influence those around you. Your own body can also have an impact on how you feel about yourself.

“When you pretend to be powerful, you are more likely to actually feel powerful,” Cuddy says.

Nervous for a job interview? Don’t feel like raising your arm in class? Fake it till you make it, Cuddy advises.

Simon Sinek: How great leaders inspire action

Why is it that Martin Luther King led the Civil Rights movement? Why is Apple one of the most successful computer companies?

Great leader and successful companies act and communicate in the exact same way, author Simon Sinek says.

“All I did was codify it, and it’s probably the world’s simplest idea,” Sinek says. “I call it the golden circle.”

Jill Bolte Taylor: My stroke of insight

When she was 37 years old, neuroanatomist Jill Bolte Taylor had a stroke.

“How many brain scientists have the opportunity to study their own brain from the inside out?” she says.

In this video, Taylor explains how she watched as her brain functions gradually shut down, one by one, and how the experience informed her work as a scientist and a public speaker.

Brene Brown: The power of vulnerability

How do we learn to embrace our vulnerabilities to live from a place of authenticity?

How do we obtain the courage to recognize that we are worthy of love and joy?

These are some of the questions social worker Brene Brown touches on in her presentation, after spending 10 years studying vulnerability, courage, authenticity and shame.