0:00
8:30
Manda indietro di 15 secondi
Manda avanti di 15 secondi
Yosemite National Park: Since the glaciers retreated around 15,000 years ago, rock fall has been the major force of change in Yosemite Valley. Geologists work to understand this force of nature in order to protect the millions of visitors who come here each year.

Altri episodi di "Yosemite Nature Notes"