It is kind of amazing to me that we, as a country, decided to make our national parks when we did. The 19th century seems to be marked by expansion, imperialism and building of capitalistic and western infrastructure. We (the US) fought a war with our neighbors and with ourselves, destroying the eastern landscape and killing over 600,000 of our own people. It is kind of amazing to me that in this century we decided that our natural beauties were worth being conserved.
I am amazingly grateful for this. Grateful that a small group of people went out into nature and fell so in love with it that they fought to keep it safe. It really is amazing as I am sure they had a hell of a hard time trying to convince people that not only was nature worth preserving, but that we should spend taxpayers money to protect it.
That being said there is still so many amazing places on this globe that are not protected, and once they fall to industrialization they will be gone forever. There is a really awesome documentary about Patagonia, and what is happening down there, called 180 degrees south. In it they use the history of Easter Island as a micro example of what happens when we do not respect, care for and protect our planet.