Use left pairs for crossed vision; use right pairs for straight vision.
Use top pairs for crossed vision; use bottom pairs for straight vision.
Entrance to glacier ice cave in mouth of Ellsworth Glacier at Day Harbor.
Upper part of glacier ice cave in avalanche chute at Byron Valley near Portage.
Arch in limestone along Iron Creek north of Nome on Seward Peninsula.
Entrance to lava tube cave at Bogoslof Hill on St Paul of Pribilof Islands.