Hidden treasures like historic documents, manuscripts, and maps all can be found at the Stony Brook Special Collections and University Archives.

Kristen Nyitray, the head archivist of the fascinating collection, says they have Dutch maps dating back to the 17th century that depict Long Island for the first time as an island.

Also in the collection are 30,000 books - the oldest from the 1400s. It also includes a book about East Hampton history from 1761.

However, it's two letters from 1779 and 1780 that are considered the crown jewels of the collection. They're penned by General George Washington during the American Revolutionary War - the letters document spy activities in Setauket.

The public can see the maps, letters and books first hand by making an appointment with the Stony Brook Special Collections and University Archives.