Uncharted 2: Among Thieves has surfaced online and it's looking absolutely gorgeous. The images show some very ambitious action sequences and intense environments (such as a gun battle on a moving train, and deadly drop zones like the gutted train car hanging over a cliff pictured above).
Of course, concept art can only show the intent of designers and not the final content found in the game. Though, those lucky enough to have seen the leaked GDC gameplay footage might attest that the transition from concept to game is working out just fine. IGN has a few more concept paintings to check out, including an area that looks like it could be Shangri-La.