Marriage certificate, Divorce Decree, Bank Statements, Utility Bills, Tax Returns/Transcripts, Apartment Leases, Dog License showing joint ownership, LOTs of photos, Travel Itineraries, Life Insurance Policy, Signed Affidavits, Copy of my Ex's Driver's License, US Passport and birth certificate. But again, the IO did not ask me to show him anything and did not bring up anything about my previous marriage nor did he ask any personal questions. Just reviewed the application and asked the civics questions.