The Giant Magellan Telescope (GMT) is being developed by a consortium of major US and international educational and research institutions. The 25 meter next-generation telescope will be located at Las Campanas Observatory in Chile. The project has completed the conceptual design of the telescope and enclosure and is currently in the Design Development Phase leading up to construction. Various refinements have been made to the telescope structure since the Conceptual Design. These include the modification of the upper truss structure to reduce image blur due to wind shake and the design of a 9 meter rotator for large Gregorian instruments. An integral field spectrograph has been added to the candidate list of first-generation instruments. The primary mirror for GMT consists of seven 8.4 meter diameter segments. The first of the six, highly aspheric, off-axis segments has been cast and generated at the University of Arizona SOML with completion of the mirror expected in 2009. The metrology for polishing the segments is currently being installed in the new test tower at SOML. Verification tests that independently measure the mirror figure have been designed and are also being implemented. This paper summarizes the overall design and recent progress in the technical development of GMT and in characterizing the site.