Underground marvels at Aven Armand / France

The throne pavilion in Phraya Nakhon Cave, Khao Sam Roi Yot National Park in Thailand

The throne pavilion in Phraya Nakhon Cave, Khao Sam Roi Yot National Park in Thailand

Juan’s Glacier Cave in Parque Nacional Los Glaciares, Patagonia

Exploring Abismo Anhumas in Mato Grosso do Sul, Brazil