Located at the end of State Highway 504 and 52 miles east of Castle Rock, Wash., in the heart of the volcano’s blast zone, interpretive displays indelibly portray the sequence of geologic events that transformed the landscape and opened up a new era in the science of monitoring an active volcano and forecasting eruptions. The observatory is located near the site of volcanologist David A. Johnston’s camp on the morning of the major eruption.

Photo Alex Buke