Wankel's Rotary engine found little following in Europe after the demise of NSU, but Mazda embraced the technology like RX-8 owners embrace 2-for-1 Castrol deals. Here's a 1960's educational animation from Mazda explaining why the rotary engine is an advancement on that old piston-powered buggy your grandma drives.
The best quote comes from one of the commenters below the video who exclaims "Truly genius. It has a ton of potential to be the greatest engine. I have one in my RX7 and its truly amazing, except for the gas mileage and emissions problem." It says it all, doesn't it?