How Does a piece of land become a National Park?

Question

How does an area become a National Park?

Also what are some reasons for making a piece of land a Naional park apart from protecting flora, fauna and historic sites?

lol I was really wandering coz my sister asked me and i'm not really sure. I know some reasons why land may become a national park but not how it becomes a national park.

Answer 1

A bill in Congress with support from most of the delegates, and a President willing to sign it. It could happen in a year, ten years or never, depending on whether one of our representatives in Washington D.C. decides to champion the idea.

Answer 2

an act of congress