This 736 piece puzzle from Ravensburger is mind bogglingly difficult! Every piece is one color - black - with a mix of traditional and non-traditional pieces. There are concentric circles inside a rectangle, inside another circle, inside a rectangle! Sure to drive even the most gifted puzzler a little crazy. Take a stab in the dark with Ravensburger's Krypt Black jigsaw puzzle! Finished size: 27" x 20"