What can I say about Richard Serra (b. 1939), it's kind of hard to understand the magnitude of his work without seeing it firsthand.
Big Steel Structures
The two installations I have seen have had big curving steel spirals. You can walk inside them. These steel walls surrounding you, in an almost scary way. The steel is 2 inches thick and at least 12 feet tall by my approximation. Each spiral is actually made up of 6 curved sheets that are spot welded together when the piece reaches its destination.
He worked in steel mills to support himself through college, and eventually through his intelligence and meanderings through art circles he began to realize his creative talents.
His work has been disliked by some, when it has been put in public spaces. Personally, I find it astounding. The pieces are made in such a way that they distory your view of space. The bottom spiral radius is not the same as the top spiral radius, but there is steel between them... confusing? He designs these works using CAD and has them bent on machines that were made for creating ship hulls.
Torqued Elipses was the first show of his I saw, and Torqued Spirals, Toruses and Spheres the second. He has other interesting, more conceptual pieces, but the spirals are the most amazing.