august

decorous, proper, seemly

grave, grim, po-faced [British], sober, somber (or sombre)

aristocratic, elegant, elevated, handsome, lordly, magisterial, majestic, noble

colossal, monstrous, prodigious, stupendous, tremendous

kingly, lordly, princely, queenly

awesome, awful, cosmic (also cosmical), sublime, wondrous

formidable, impressive, prepossessing, redoubtable

apocalyptic (also apocalyptical), inflated, operatic, overblown, pompous

marvelous (or marvellous), superb, terrific, wonderful

extravagant, lavish, luxurious, opulent, palatial, palatine, sumptuous

gorgeous, resplendent, splendiferous

extraordinary, killer, remarkable, sensational, striking

celestial, divine, heavenly