Transfer to the airport and fly to Ushuaia, the world's southernmost city, on the island of Tierra de Fuego. The city has grown rapidly in recent years, partly as a result of government incentives to settlers, and its establishment as a Free Port, and partly a tourist centre - most Antarctic cruises leave from the port here. The setting is spectacular; jagged mountains hem in the town down to the shore of the Beagle Channel. Transfer to your hotel.
In the afternoon, board a catamaran at the pier and sail along the Beagle Channel, past some of Ushuaia's important buildings - the Maritime Museum and Museum of the End of the World, and its industrial suburbs. Beyond, the scenery is more spectacular, with fine views of the mountains that form a backdrop to the world's southernmost city.
The catamaran then sails to mid-Channel, southwest towards the lighthouse on the Les Eclaireurs archipelago. On one of these islands, you can see remains of the Monte Cervantes, shipwrecked in 1930. Continue to Sea Lion Island, which is circumnavigated for about 20mins to see the eponymous habitat, and Bird Island to see cormorants, giant albatrosses, petrels, and skuas. Return through Paso Chico, which frames the Martial glacier beyond the city of Ushuaia.