In the far right corner in the Los Angeles Central Library’s History & Genealogy section are dozens of gray filing cabinets with slim drawers; they contain the 100,000 maps in the library’s collection, some of which date back to the 16th century. It’s hard to comprehend how important these maps were, but many of L.A.’s long-forgotten street names and places would have been lost if not for the often purely commercial cartographic skills of real estate agents, automobile clubs, city engineers and people who loved the city. Ask to see the “Dog & Pony” selection — some of the most beautiful and unusual pictorial maps — or find your street in the huge insurance Sanborn Fire Atlas, or peruse the ancient Thomas Guides (remember them?). Retrieve the 1924 map of “Mesmer City,” a proposed development between Culver City and Mar Vista, which was not to be. The librarians say the collection belongs to everyone. So get in there and touch history. 630 W. Fifth St., dwntwn. (213) 228-7400, lapl.org.