The 100 WondersProjectSearch
Crater Lake seen from Rim Village in winter

Interactive explanations

Earth Lab.

Slow down a process, change your viewpoint and learn to read the landscape.

PhotographWolfmanSF · CC BY-SA 3.0

Inside a caldera.

World mapMove the stage control to see an illustrative sequence of magma withdrawal, collapse of the overlying ground, and a later lake. This is not a model of a particular eruption.Schematic cross-section · not to scale

The simplified mechanism follows US National Park Service caldera interpretation. Real volcanic systems and their timelines are more complex. The lake stage is one possible later outcome, not a necessary result of caldera formation.

Read the caldera explanation

Read a valley from its shape.

World mapSimplified cross-section · real valleys record more than one process
This simplified V-shaped profile introduces incision by a river. Real river valleys vary with rock, history and the processes acting on their slopes.

Background: NPS glacial landforms. The control compares forms, not a measured simulation of erosion or a prediction of glacier retreat.

Read the glacial valley explanation