Iceberg A23a measures 40 by 32 nautical miles, according to the U.S. National Ice Center. For comparison, Hawaii's island of Oahu is 44 miles long and 30 miles across .

Iceberg A23a measures 40 by 32 nautical miles, according to the U.S. National Ice Center. For comparison, Hawaii's island of Oahu is 44 miles long and 30 miles across .

The world's largest iceberg, A23a, is moving into the open waters near Antarctica after being essentially stuck in place for decades. It's seen here in satellite imagery from Nov. 15.

"It's a trillion tons of ice," as one expert told NPR. Now the largest iceberg in the world, A23a, is on the move after decades of being grounded on the seafloor.

While B-22A is a large iceberg, it isn't anywhere near the largest one ever recorded. That record is held by an iceberg called B-15, which measured a massive 4,247 square miles, ...

The world's biggest iceberg — a wall of ice the size of Rhode Island — is lumbering toward a remote island off Antarctica that's home to millions of penguins and seals.

Iceberg A23a measures 40 by 32 nautical miles, according to the U.S. National Ice Center. For comparison, Hawaii's island of Oahu is 44 miles long and 30 miles across .

"It's a trillion tons of ice," as one expert told NPR. Now the largest iceberg in the world, A23a, is on the move after decades of being grounded on the seafloor.

"It's a trillion tons of ice," as one expert told NPR. Now the largest iceberg in the world, A23a, is on the move after decades of being grounded on the seafloor.