06/16/2026
Mount Katmai, Alaska ⛰️
Before 1912, Mount Katmai was a massive snow-covered stratovolcano towering above the Alaska Peninsula.
Then came the largest volcanic eruption of the 20th century.
As magma drained during the 1912 Novarupta eruption, the summit of Mount Katmai lost support and collapsed into the earth, creating a giant caldera nearly 3 miles (4.8 km) wide.
Today, a deep blue crater lake fills the space where the mountain's summit once stood.
This isn't a crater blasted out by an explosion—it's an entire mountaintop that fell inward.
Swipe to see one of Earth's most dramatic volcanic transformations.
📍 Mount Katmai, Alaska, USA
