First, separate the material from the landform.
At the Grand Canyon, the exposed rocks record a much longer history than the canyon’s excavation by the river. A cliff face, a sedimentary layer and a side valley therefore belong to different parts of the explanation. The question “How old is it?” needs a more precise subject before it has a useful answer.
Read the geological or environmental reference ↗ · Open the wonder guide →
Then look for processes that continue.
Volcanic islands show how construction, erosion and ecological change can operate together. A lava flow has a particular history, but the island as a whole contains many episodes. In an active volcanic landscape, the latest official access information belongs alongside the geological explanation.
Read the geological or environmental reference ↗ · Open the wonder guide →
Ice both records and reshapes.
A glacier is moving ice, not a permanent sculpture. Crevasses, calving fronts and moraines reveal different aspects of that movement. The ice visible on one visit is part of a changing system, while the broader valleys preserve evidence of earlier glaciation.
Read the geological or environmental reference ↗ · Open the wonder guide →
A dune is younger than its sand.
Wind can rearrange sediment into forms whose shape changes much faster than the grains themselves. At Sossusvlei, light makes those forms easy to read. A dune’s crest, a sheltered hollow and an interdune pan tell related but different stories.
Read the geological or environmental reference ↗ · Open the wonder guide →
Living things can build a landscape.
Reef environments are shaped by living organisms as well as waves, water conditions and sea-level history. The structure beneath a swimmer and the individual animals living on it do not share a single timescale. Looking closely reveals this overlap of construction and habitat.
Read the geological or environmental reference ↗ · Open the wonder guide →
The present view is a meeting of histories.
A mountain scene combines the formation of rock, uplift, erosion, glaciation, water and living ecosystems. No single date can explain everything in the photograph. Start by identifying one feature, then ask what process made it and what continues to change it.
Read the geological or environmental reference ↗ · Open the wonder guide →