What machinery has the highest pressure in the world? Do you know what it is only good for?

Question

What machinery has the highest pressure in the world? Do you know what it is only good for?

Answer 1

Diamond anvils create pressures of tens of millions of pounds per square inch.  They are used for research into the effects of pressure on various materials.  Such pressures exist deep inside the earth, so this kind of research helps geologists predict what goes on there.