With a surface area more than twice that of Greater London's, A23a is the biggest iceberg on the planet, having calved from the Filchner-Ronne Ice Shelf in 1986.

The frozen leviathan is now on the move across Antarctica seas once more having spent the last few months going round in circles.

Its first few decades of freedom were anticlimactic, sitting anchored on the sea floor until finally in 2020 it began inching towards the Southern Ocean, only to become trapped by a swirling vortex of water earlier this year.

These particular ocean vortexes are known as Taylor columns, caused by the presence of underwater mountains. The circulating currents that result can make it difficult for icebergs to break free, but A23a has done just that.