Ocean World

Earth change. cities, houses, mountains, deserts, forests, lost and unsee. About 80% world full of water and 20% humans, animals lived at surface. The land that stay right now is gone. Earth became blue with water, oceans win the cycle evolution. Survivors build they're own city from metals which it called City of Metal. Powerful city to protect humans and remaining animals inside. Just a matter of time, the city will drown... How humans survive then?