[The following is from getty.edu web site]

Located on the south facade of St. Vitus Cathedral in Prague Castle, The Last Judgment is
considered the most important exterior monumental medieval mosaic north of the Alps. The mosaic
encompasses 84 square meters (904 square feet) and depicts the Last Judgment in triptych form. It
was completed in 1371 at the request of Charles IV, king of Bohemia and Holy Roman Emperor, who,
during his reign, made Prague the empire's center of power, religion, and knowledge. In the
mosaic's center panel is the figure of Christ surrounded by angels; kneeling beneath them are the
figures of six saints of the Czech lands. On the triptych's two side panels are images of heaven
and hell. Thirty-one shades of colored glass, plus gilded tesserae, can be found in the approximately
one million glass pieces that compose the mosaic. Originally, the entire background of the mosaic
was gilded, hence the name of the southern portal of the cathedral—The Golden Gate.

The Golden Gate underwent a conservation project from 1994-2008. It looks great!