Ice wall twice the size of Greater London runs aground near British island - The nearly one-trillion-tonne block of ice, known as A23a, has grounded on the continental shelf off South Georgia island

The British Antarctic Survey says nutrients from the grounding and melting of the megaberg known as ‘A23a’ may boost food for penguins and seals.

The world's largest iceberg appears to have run aground off the coast of a remote British island home to millions of penguins and seals — potentially threatening local wildlife, but also providing an opportunity for research into such rare "megabergs.