Greubel Forsey has made quite a name for themselves with their unparalleled commitment to traditional watchmaking. Their Double Tourbillon 30° Technique line, in particular, made a big splash when it was launched several years back, owing to two tourbillons constantly rotating in a single case. Now, they upped the ante by reintroducing the timepiece in a sapphire crystal case made out of a single block. This is certainly a case to show, as it also allows a completely unobstructed view of the watch’s tour de force—the precious movement itself. If you think this is the watch for you, get ready to fly to the U.S. where the only eight pieces ever produced are sold, for slightly over US$1.1 million each.