This paper analyzes three high-profile European case studies of post-9/11 terrorist attacks (Istanbul [2003], Madrid [2004], and London [2005]). It also examines targeting and tactical information gleaned from several failed/foiled plots in Europe. Although the general findings of this paper can be applied to any type of large scale terrorist attack, this study focuses on those attacks perpetrated by Muslim extremists since this subset currently constitutes the most prominent terrorist threat to the U.S.