Sentence:  Here, where a Cæsar stood two thousand years ago, the traveller from another continent (though not from New Zealand) stands to-day, to muse—at Pæstum, as at Pompeii—on the fate which overtakes all human things, and at last <WSD>whelms</WSD> man and his works in one undistinguishable ruin. 
Meaning of the word marked with <WSD> tags:  To ruin or destroy.