layer

All around me were crumbling walls that revealed their history in layers, like rings on a tree: from grey stone, to copper colored brick, to cement, to the green and white flaking paint.

It involves drilling into the earth and directing a high-pressure mixture of water, sand and chemicals at a rock layer, to release the gas inside.

The upper layers of the Earth in the vast Pacific region are split into sections - tectonic plates - which are all moving relative to one another.

But he never imagined the scale of it, describing it as an "attack on every layer of life in Gaza, from infrastructure, electricity, the water supply, the sewage system, the hospitals, schools and universities."

Along the California coastline, overlapping layers of regulations make it hard to build at any time.