Like the prize at the end of a treasure map, there’s something new and special tucked away in the Merrill Lynch Building at 7825 Fay Ave., and it’s of worldwide prominence. It’s not visible from the street — you have to enter the unassuming complex and take the elevator to the courtyard level — but inside is a view of history dating as far back as year 1318. La Jolla businessman and philanthropist Mike Stone unveiled the Map & Atlas Museum of La Jolla in a private opening party on Feb. 8. The gallery-like exhibition was born from his personal repertoire of about 500 rare maps that he’s collected and stored in a private vault for the last 20 years.  “It was just not right having them locked up in an oversized closet,” said Stone, 48, who also serves on the board of the San Diego Museum of Art and is an advisory board member for the Norman B. Leventhal Map Center at the Boston Public Library. “This material needs to be seen and appreciated.” The museum, which offers free admission, is believed to be the only one of its kind west of the Mississippi. Its rare items are viewable by appointment only for at least a month, but Stone hopes to open for regular business hours soon. Displayed in cases and on walls, the maps are arranged by themes or time periods. Some were used to find wine in California, others to find fish in the deep seas. One section, titled “The Heavens,” contains maps of the dream-like projections of early thinkers, with many cartographic pieces showing gods blowing wind over land or sea monsters dwelling in the ocean. La Jolla native Barry Lawrence Ruderman, who Stone introduced at the Feb. 8 event as “the most dominant online dealer of antique maps in the world,” worked closely with Stone in the opening of the museum and even sold him a few maps. Ruderman, who runs www.rare maps.com, said one of the main goals of the museum is to serve as an educational resource for kids. He enthusiastically showed off a few rare local items, such as a centuries-old map of Mission Bay and a 3-D paper mâché map of San Diego’s coastline, which was used in the early 1900s as a promotional prop for land sales agents. “This museum rivals any public display of maps in the world,” said Ruderman. “There are so many rare and unique things in this room, but the most rare and unique thing is Mike [Stone].”