The walk from the bridge across the Firehole River into the steam and mist covered pathways truly transports you to some other world. Words are insufficient to describe what it's like to walk along boardwalks through churning clouds of sulfur-smelling steam over the vast expanse of turquoise boiling water in Excelsior Geyser. Unbelievable to see that much clear blue water! It’s a photographer’s dream.The intense steam will make you feel as though you are walking to the edge of hell...and knows how to remind how small you are.
One of the highlights of the whole national park is Grand Prismatic Spring. This is a huge oval pool 370 feet across and 120 feet deep that is surrounded by unusually colorful bands of algae and travertine terraces, with a wavy run off channels, giving the appearance, from above, of a giant blue star. The pool constantly bubbles and steams, forming clouds of hot mist that blow around in the breeze and sometimes make the pool itself hard to see properly but adding to the enchantment of the scene. A half mile boardwalk trail runs part way around the spring, past two much smaller pools (Opal and Turquoise) and to the adjacent crater of Excelsior Geyser, formerly the largest geyser on Earth. This is now another big, steaming, simmering pool, the remnant of an explosive eruption in the nineteenth century which destroyed the geyser. The deep blue pool produces up to 4,000 gallons of water a minute, which flows down several colorful drainage channels into the Firehole River.
