See the context of this sign.

Before the Collapse

When Mt. Mazama collapsed about 6,300
years ago, it left behind evidences of its
former self. Like X-ray photos, the steep caldera
walls reveal the interior of Mt. Mazama before
its fall. From this point several pre-collapse
volcanic fatures can be identified.

The massive gray monolith on the rim ahead is
Llao Rock. It formed when a large outpouring
of lava filled an explosion crater on the north
slope of Mt. Mazama. When Mt. Mazama collapsed,
part of the hardened lava flow broke off
and fell into the caldera, leaving the downslope
portion perched on the rim.

The jagged, colorful spires of Hillman Peak in
the forground are the remains of a secondary
volcano which erupted on the side of Mt.
Mazama. This satellite cone attained a height of
1,000 feet (300m). Erosion here has exposed a
maze of clogged and solidified lava conduits
that fed the Hillman volcano.

Don't miss the rest of our virtual tour of Crater Lake National Park in 1757 images.