An industrial accident in Indianapolis nearly cost Muir his sight. This experience prompted him to re-evaluate his life and dedicate himself to exploring the natural world.

Following his recovery, Muir embarked on a thousand-mile walk from Indiana to the Gulf of Mexico. This journey, documented in his book 'A Thousand-Mile Walk to the Gulf,' shaped his views on nature and conservation.

Muir arrived in California and immediately fell in love with Yosemite Valley. He spent considerable time exploring the region, studying its geology, flora, and fauna.

Muir worked various odd jobs in Yosemite, including as a shepherd and a sawmill operator, to sustain himself while dedicating his time to exploring and studying the valley. He famously lived in a small cabin near Yosemite Falls.

Muir extensively explored the Sierra Nevada mountains, making numerous ascents, studying glaciers, and documenting the region's natural history. He developed his theories on the glacial formation of Yosemite Valley during this period.

Muir began his travels to Alaska, where he studied glaciers and the region's unique environment. He named Muir Glacier after himself and wrote extensively about his Alaskan experiences, further popularizing the region.

Muir continued to travel and explore, visiting various parts of the world, including South America, Africa, and Australia. He documented his observations and advocated for the preservation of wilderness areas globally.