The volcanic activity in Hawaii today is part of the ongoing Pu’u O’o eruption—the longest-duration eruption ever recorded on Kilauea. The Pu’u O’o eruption has been active, with varying levels of intensity, since January of 1983. Looking back a few decades, Kilauea’s previous record-holder was the spectacular Mauna Ulu eruption, which lasted from May of 1969 until July of 1974, generating amazing lava fountains, cascading lava falls, and eventually adding 230 acres of new land to Hawaii’s Big Island. As we wait to see how these new eruptions will play out, take a moment to view some of Kilauea’s most striking photos from the Mauna Ulu eruption, which ended only 40 years ago.