Punta Arenas is the southernmost city of any size in Chile and the gateway to the Strait of Magellan, which is the reason for everything here: penguins on Isla Magdalena and at Seno Otway, whales in the Francisco Coloane marine park, and the boats to Antarctica.
It is also where Patagonian logistics are arranged. More of the operators below sell transport and charter than sell an experience.