At first glance, Earth's map looks fixed. But geologists have uncovered a surprise in the southwest Pacific. Beneath New Zealand and New Caledonia lies Zealandia, a large region mostly underwater covering about 4.9 million square kilometres. Unlike normal ocean floor, Zealandia has thick, light continental crust made of rocks like granite and limestone. It rises higher than deep ocean basins and has clear edges like other continents. Zealandia used to be part of Gondwana, the ancient supercontinent. Around 80 to 90 million years ago, it stretched and thinned, drifting away from Australia and Antarctica. This made it sink so 94% is underwater today. But it remains a continent under the sea. Islands like New Zealand and New Caledonia connect with Zealandia's geology and ancient mountain belts, proving geological continuity. Its size is similar to greater India before it joined Asia and much bigger than microcontinents. Oceanic crust separates Zealandia physically and tectonically from Australia. This new understanding shows continents don’t always stop at the shoreline. Zealandia offers a unique chance to study how continents break, stretch, and sink. It reminds us Earth’s surface still holds hidden surprises, waiting beneath the waves.