Measuring roughly 1,350 square miles (3,500 square kilometers) across, A23a is the world's largest and oldest iceberg according to AFP News. Its imposing size and slow, steady movement have captivated oceanographers and researchers alike, though predicting its exact path has proven difficult due to the unpredictable forces of ocean currents.

T​he largest iceberg in the world is headed toward an island with a massive population of penguins and seals, according to satellite tracking from NOAA. T​he trillion-ton slab of ice that scientists call a "megaberg" broke off from the Antarctic’s Filchner Ice Shelf in 1986.