I'm the reason your daughter's so obsessed.

"I’m a very calm person. That helps me in tennis and in life."

Winning is about heart, not just legs. It's got to be in the right place.

Gymnastics is what I do, not who I am.

"The only way to get rid of a temptation is to yield to it."

The climate system is extraordinarily complex, and our understanding of it is still evolving.

To teach mathematics is to inspire the next generation of thinkers and problem solvers.