Both Gentoo and Adélie penguins breed on Petermann Island. At 1.8km (1.1 mi) by 1.2km (0.75 mi), it's a fairly small island of volcanic origins.
Seeing all these penguins nesting, many with young chicks, became a somewhat common sight throughout Antarctica. It was fun to just stand and observe them for a while, as the antics of penguins are always amusing.
View of Petermann Island, covered in penguins.