Here's why some Hawaiians are so angry, they keep marching up a volcano

HILO, HAWAII - Hundreds of protestors flocked to Mau na Kea on Wednesday to block construction of the world's largest optical telescope.

It's the second time in the past few months that demonstrations have broken out on the dormant volcano.

Astronomers want to build the Thirty Meter Telescope (TMT) there because the cloudless air and dark skies offer one of the most pristine windows into the universe on Earth. From such a lofty perch, the observatory could reveal parts of the cosmos we've never glimpsed before.

But some native Hawaiians consider the summit sacred and a home to several deities.

As I marched alongside protestors who wound their way up the mountain, however, I learned their animosity stems from something much bigger than a giant telescope or sacred mountaintop.