About 300 protesters are attempting to halt construction of the Thirty Meter Telescope (TMT), which is supposed to break ground this week on Mauna Kea, the tallest mountain on the big island of Hawaii. About half a dozen protesters chained themselves to a grate in the road at the base of the dormant volcano Monday morning in an attempt to block workers from accessing the only paved road onto the what they say is a sacred site, NPR reports. In Native Hawaiian culture, the area is hallowed ground that contains “ahus,” or religious altars made of stones, and serves as a burial ground for many of the island’s ancestors. Scientists believe that Mauna Kea’s summit is the ideal location for the TMT because of its dry air and absence of clouds and light pollution. The Hawaii Supreme Court ruled in October to reinstate a building permit that was revoked years earlier, which has spurred construction of the telescope. It is estimated that the TMT will take 10 years to complete and will be the largest instrument of its kind in the Northern Hemisphere.