Mantle material can sink at a plate boundary, and then flow back upward farther away, pushing on the crust - a process called small scale convection.

Here Earth's crust pulls apart, and upwelling magma cools and forms new crust that spreads away from the ridge in the great recycling process known as plate tectonics.

Taking and developing photos using the so-called "wet-plate" process was a meticulous, multi-step procedure that required more than one "camera operator" and lots of chemicals and equipment.