Apocalyptica is a Finnish cello metal band, composed of classically trained cellists and, since 2005, a drummer. Three of the cellists are graduates of the Sibelius Academy in Helsinki, Finland. Their music features elements from cello metal, neo-classical metal, progressive metal and symphonic metal. Worlds Collide is the sixth studio album from cello metal/heavy metal group Apocalyptica. It includes special guests Till Lindemann, Corey Taylor, Adam Gontier, Dave Lombardo, Tomoyasu Hotei, and Cristina Scabbia.