Tourists crossing the mountains that rim the volcanic caldera of Deception Island, South Shetland Islands, Antarctic Peninsula, Antarctica, Polar Regions

Wahban Crater (caldera) in Hejaz Mountains northeast of Jeddah, Saudi Arabia, Middle East

Oia village perched on Santorini caldera rim, Oia, Santorini, Cyclades Islands, Greek Islands, Greece, Europe

Wall of the Minoan caldera, with town of Thira (Fir) perched on rim, Santorini, Cyclades, Greek Islands, Greece, Europe

Oia village on rim of volcanic caldera, Santorini, Thira, Cyclades, Greek Islands, Greece, Europe

Aerial view over the houses of Fira Town, the capital of Santorini (Thira), perched on the Caldera Rim, Cyclades, Greek Islands, Greece, Europe

Aerial view over the houses of Fira Town, the capital of Santorini (Thira), perched on the Caldera Rim, Cyclades Islands, Greek Islands, Greece, Europe

Aerial view over the illuminated houses of Fira Town at dusk, the capital of Santorini (Thira), perched on the Caldera Rim, Cyclades Islands, Greek Islands, Greece, Europe

Fira Town, the capital of Santorini (Thira), perched on the Caldera Rim, Cyclades Islands, Greek Islands, Greece, Europe

Aerial view over Fira Town, the capital of Santorini (Thira), perched on the Caldera Rim, Cyclades Islands, Greek Islands, Greece, Europe

Curious adult chinstrap penguin (Pygoscelis antarctica) inspects the camera on Deception Island, Antarctica.

Chinstrap penguin (Pygoscelis antarctica) parents with chick high on the caldera rim on Deception Island, Antarctica.

Curious adult chinstrap penguin (Pygoscelis antarctica) inspects the camera on Deception Island, Antarctica.

Chinstrap penguin (Pygoscelis antarctica) parents with chick high on the caldera rim on Deception Island, Antarctica.

Curious adult chinstrap penguin (Pygoscelis antarctica) inspects the camera on Deception Island, Antarctica.

Church in Fira on the rim of the caldera, Santorini, Cyclades, Greece, Europe