The oldest sequoias can live for more than 3,000 years, their bark resisting insect attacks and helping them survive countless wildfires over the millennia.

Gone are the gift shop, suffocating fumes from a chugging diesel tram and 115 spaces of parking lot asphalt that once cluttered the site, a major tourist destination four hours’ drive from San Francisco.

The removal of asphalt helps protect the trees’ shallow root system from compaction, allows water to flow naturally again, and reduces damaging air pollution from excess vehicles.

Four miles (6.5 kilometers) of new trails and bridges have been constructed. A new boardwalk through part of the grove is elevated over sensitive areas and facilitates handicapped access to view the trees.

People stand in line to photograph one another at the California Tunnel Tree, a surviving sequoia through which a wagon-sized hole was long ago bored.

But like the rest of the forest, Mariposa Grove never closes, so after the last shuttle bus returns and the road gate is reopened, more adventurous visitors can drive to the tiny parking lot and hike through the night in the ancient woods.