Numerous phone interviews just to get your foot in the door. Once making it through that process they invite you to the main headquarters for an interview circuit with 6-8 different interviewers in turn. Non-stop questions for 6 solid hours, many repeated with the expectation of varying responses. Focus on their internal leadership values and provide real-life examples for each one. Final two interviews with upper management personnel (need to be sharp at the end so conserve your energy). One slip with them can make or break the opportunity. No reason or explanation provided for refusal or denial of an offer.