You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "when did the great sand dunes become a national park?" whose answer is 2000-2004.
Each document should contain about 30 words, and these documents should contain useful information.

Query: when did the great sand dunes become a national park
Useful Output:

Doc 1: The idea of establishing this rare and remarkable dune field as a National Monument originated on a summer day in June 1930, during a PEO luncheon presentation
Doc 2: 4) 3,000 years ago to Present Day: The animation zooms into the forming dunefield, which continues to grow at the base of the mountains. Storm
Doc 3: Formerly classified as a national monument, Great Sand Dunes was established as a National Park in 2004. The sand dunes formed from sediment
Doc 4: On March 17, 1932, Great Sand Dunes was officially proclaimed a National Monument by authority of President Herbert Hoover.
Doc 5: On November 22, 2000, Great Sand Dunes National Monument became Great Sand Dunes National Park and Preserve through an Act of Congress. But