Deception Island in the South Shetlands is the collapsed caldera of an active volcano. We sailed through the narrow entrance of Neptune’s Bellows and saw the 12 km wide amphitheatre of the flooded caldera. Going ashore at Whalers bay we visited the remains of the old whaling station Hektor and the former British Research Base. The area was like a moonscape of dark volcanic sand and rock. The black volcanic beach was hot and steamy due to geothermic activity and the ideal spot for some to take a polar plunge. We climbed to the spectacular Neptune’s window for views across the whole caldera. There were some chinstrap penguins, seals, skuas and cape petrels.