Matsyapurana 140.73

140.73

sagopuro mandarapādakalpaḥ prākāravaryastripure ca so 'tha
taireva sārdhaṃ bhavanaiḥ papāta śabdaṃ mahāntaṃ janayansamudre //

There was a tremendous noise when the gates, the compound wall and the various buildings inside Tripura, tumbled into the ocean with great violence That Tripura was majestic like the mountain with thousands of peaks The very same Tripura with all its habitations became the morsel of fire and remained only in name—73 74