How long does it take to change a flat plain into mountains?

Im not for sure but i think it takes a couple hundred years (or according to the climate)

I think that it's more than we can imagine. There are some scientists say that the biggest desert in the world was a huge ocean thousands years ago!!! The face of Earth is the knowledge we are not so sure now. (Maybe we'll never know) Earth is changing little by little, day by day.……
It do really takes more than everything we can imagine ……
Maybe thousands of years later, someone could find out my cellphone ……(My iPhone 5s, it's already missing for months!!! )

Gravity bc it’s gravity