Getty Images
MS Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
MS Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
Getty Images
MS Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
MS Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
Getty Images
MS TU Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
MS TU Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
Getty Images
MS PAN View of caves and caverns / Western Cape, South Africa
MS PAN View of caves and caverns / Western Cape, South Africa
Getty Images
MS PAN Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
MS PAN Shot of Akiyoshido Cave / Yamaguchi, Yamaguchi Prefecture, Japan
Getty Images
Low Angle tilt-up - Stalagmites jut from the floor of Carlsbad Caverns. / New Mexico, USA
Low Angle tilt-up - Stalagmites jut from the floor of Carlsbad Caverns. / New Mexico, USA
Getty Images
A spelunker is silhouetted at the entrance of a cave as he puts on his headlamp.
A spelunker is silhouetted at the entrance of a cave as he puts on his headlamp.
Getty Images
A spelunker pauses at the entrance of a cave to put on his headlamp.
A spelunker pauses at the entrance of a cave to put on his headlamp.
Getty Images
Tourists on Pamukkale Travertine pools and terraces.
Tourists on Pamukkale Travertine pools and terraces.
Getty Images
Tourists on Pamukkale Travertine pools and terraces.
Tourists on Pamukkale Travertine pools and terraces.
Getty Images
Tourists on Pamukkale Travertine pools and terraces.
Tourists on Pamukkale Travertine pools and terraces.
Getty Images
Tourists on Pamukkale Travertine pools and terraces.
Tourists on Pamukkale Travertine pools and terraces.
Getty Images
Bats hanging in a cave move to avoid light being directed on them.
Bats hanging in a cave move to avoid light being directed on them.