In January 2025, it measured around 1,410 square miles, earning it the Guinness world record for the largest existing iceberg. According to data by the US National Ice Center, several other icebergs have now overtaken A-23A in terms of total square miles. Experts believe they’re scour marks that date back to a time when A-23A was dragged across Antarctic bedrock hundreds of years ago. “I certainly don’t expect A-23A to last through the austral summer,” retired University of Maryland Baltimore County scientist Chris Shuman told NASA. A-23A left the relatively shallow waters near the Antarctic ice shelf in 2020, and spent several years drifting and spinning.