Prague Marathon is the biggest and most important marathon of the Czech Republic. It is always held in early May, and features the highlights of the wonderful old town. Prague Marathon offers the classic distance as well as a two Half Marathon relay race.
I ran Prague Marathon as marathon no. 6 of my 12 Marathons in 12 months project and I really loved it, except for the cobblestones and tram tracks. But that is something you probably have to accept when running in an old historic city like that.