The first mirror for the Giant Magellan Telescope (GMT) has been completed. This 8.4-meter (27.5-foot) mirror is the most challenging large astronomical mirror ever made. Scheduled to become operational in the next decade, GMT will be the first in a new generation of giant telescopes to explore the nature of dark matter and dark energy, and glimpse the formation and evolution of extrasolar planets, stars, galaxies, and black holes. The GMT will peer more deeply into the universe's hidden history than humans have ever attempted. The instrument's combined mirrors will be sensitive enough to detect a candle on the moon, or to see the face on a dime 200 miles away.