Arched iceberg floating off the western Antarctic Peninsula, Southern Ocean

An ocean's frozen cathedral. Arched iceberg, western Antarctic Peninsula, Southern Ocean

A sculpted arch of ice rises from the Southern Ocean along the Antarctic Peninsula, one of the fastest-warming regions on Earth. This formation began as compacted snow that turned into glacial ice over thousands of years. Eventually, part of a glacier or floating ice shelf fractured and broke free—a process known as calving—creating a drifting iceberg.

Icebergs are classified by size and shape. To qualify, a mass must tower more than about 5 metres above sea level, yet nearly 90% of it remains hidden below the surface. Flat-topped 'tabular' forms are common in Antarctica, while eroded features like this arch fall into irregular, non‑tabular categories.

Though seemingly barren, these floating giants support life. Algae cling to their undersides, feeding swarms of krill, which sustain fish, seals and whales. As ice melts, it releases nutrients that fertilise surrounding waters, turning these frozen sculptures into mobile ecosystems.