I just learned they have a museum: http://www.mazda.com/mazdaspirit/museum/index.html?link_id=sc it's in Hiroshima Japan, though you can do a bit of exploring with Google Street View http://www.mazda.com/mazdaspirit/museum/guide.html
As with its leadership in Wankel technology, Mazda remains (so far) the only automaker to have used a Miller-cycle engine in the automotive realm. The reason is simple, incredibly more expensive, (supercharger and intercoolers) very little gain in power 10hp, or mpg 15% http://www.motivemag.com/pub/feature/tech/Motive_Tech_Miller_Time_-_The_Miller_Cycle_Engine_Explained.shtml
Mazda remains the only automaker to have produced a Wankel-powered pickup truck.
Additionally, it is also the only marque to have ever offered a rotary-powered bus (the Mazda Parkway, offered only in Japan) or station wagon (within the RX-3 & RX-4 line for US markets).
Mazda also helped Ford develop the 1991 Explorer, which Mazda sold as the 2-door only Mazda Navajo from 1991 through 1994. Ironically, Mazda's version was unsuccessful, while the Ford (available from the start as a 4-door or 2-door model) instantly became the best selling sport-utility vehicle in the United States and kept that title for over a decade