Grand Canyon

Sjors Horstman has spent the last 30 years of his life at the bottom of the Grand Canyon as a volunteer for the National Park Service—one of the longest-serving volunteers in NPS history.

• By Jessi Phillips

Five landmarks in the American Southwest illustrate the limits of engineering the environment to human favor.

• By Kate Wheeling

David Brower has slipped into semi-obscurity over the years, but he deserves a place in the pantheon of environmental heroes.

• By Rebecca Tuhus-Dubrow