After a Chicago-sized iceberg broke off from Antarctica, a research vessel changed plans and went to explore an underwater world never seen before by humans.

Researchers and crewmembers aboard the Schmidt Ocean Institute’s Falkor (too), “seized upon the moment” that was presented to them, and in doing so produced the first oceanographical, biological, and geological study of the area.

Located in the Bellingshausen Sea, the King George VI ice shelf, one of the massive, mostly seaborne glaciers that sit attached to the continent of Antarctica, lost a chunk of ice the size of the greater Chicago area, or around 209 square miles.