The 'Tea Kettle,' boiling hot from Mother Earth’s hidden fires, Yellowstone Park, U.S.A.

The 'Tea Kettle,' boiling hot from Mother Earth’s hidden fires, Yellowstone Park, U.S.A.

Where Boiling River, still hot and steaming, meets the cool Gardiner in Yellowstone Park, U.S.A.

The 'Tea Kettle,' boiling hot from Mother Earth’s hidden fires, Yellowstone Park, U.S.A.

Fifteen-minute display of 'Riverside Geyser' – boiling water 100 feet in air – Yellowstone Park, U.S.A.

Fifteen-minute display of 'Riverside Geyser' – boiling water 100 feet in air – Yellowstone Park, U.S.A.

Fifteen-minute display of 'Riverside Geyser' – boiling water 100 feet in air – Yellowstone Park, U.S.A.

Great Mountain' Geyser, throwing up clouds of steam and boiling water, Yellowstone Park, U.S.A.

Great Mountain' Geyser, throwing up clouds of steam and boiling water, Yellowstone Park, U.S.A.

Great Mountain' Geyser, throwing up clouds of steam and boiling water, Yellowstone Park, U.S.A.

The 'Devil's Inkwell' bubbling and boiling over hidden fires, in famous Yellowstone Park, U.S.A.

The 'Devil's Inkwell' bubbling and boiling over hidden fires, in famous Yellowstone Park, U.S.A.

The 'Devil's Inkwell' bubbling and boiling over hidden fires, in famous Yellowstone Park, U.S.A.

Where the Earth’s great fires are still unquenched – Black Pearl Geyser, Yellowstone Park, U.S.A.

Glittering spray from "Constant" Geyser, and steam from "Black Growler," Yellowstone Park, U.S.A.

Black Growler', whose steam kills trees, and whose roaring startles tourists, Yellowstone Park, U.S.A.

Glittering spray from 'Constant' Geyser, and steam from 'Black Growler,' Yellowstone Park, U.S.A.

Black Growler', whose steam kills trees, and whose roaring startles tourists, Yellowstone Park, U.S.A.

Black Growler', whose steam kills trees, and whose roaring startles tourists, Yellowstone Park, U.S.A.