Ethereal: A waterfall cascades into an ice cave formed below Wachusett Glacier at Alaska's Glacier Bay National Park, part of one of the largest World Heritage sites
Stunning: An explorer stands inside an ice cave formed under the Muir Glacier at the Glacier Bay National Park in the U.S. state of Alaska
Electric blue: A hollowed stagnant ice remnant of the Muir Glacier, named after naturalist John Muir who documented the landscape in the 19th century
Into the depths: A climber makes their way through a cave under the Muir Glacier with ice picks (left), while another examines the stunning formations left by the melting ice which produced the carvings
In flux: Glacier Bay National Park is a constantly changing landscape consisting of 3.3m acres of rugged mountains, dynamic glaciers, wild coastlines and sheltered fjords
Eskimos, eat your heart out: Ice caves aren't only formed under glaciers. This one was made when a tunnel melted through snow that had avalanched off the slopes of the Wood River Mountains in Alaska