Within several months of Congress's passage in March 1933 of legislation that paved the way for the Civilian Conservation Corps, camps for these crews popped up across the National Park System. Glacier National Park in northern Montana wasn't left out, as eight camps were established by June to house hundreds of young men.

Seventy-five years ago, in June, 1938, Congress passed and President Franklin D. Roosevelt signed into law the bill creating Olympic National Park. With this act Americans embarked on something new in land conservation: creating a wilderness preserve large enough to protect intact old-growth forest communities and the hosts of forest-dependent wildlife they contained.

With President Obama's recent designation of five new national monuments, there now are 77 national monuments within the National Park System. Curious about the history of national monuments? Read on.

In the second part of this series Richard West Sellars, a long-time historian for the National Park Service, takes a look back at what precipitated the historic preservation movement in the National Park System.