SANTIAGO XALITZINTLA, Mexico -- Popocatepetl, the Aztec "Smoking Mountain,"
                  known as "Popo" to locals, has spewed ash, pumice and lava over the Valley of Mexico for
                  centuries, although the volcano's last large eruption came 1,200 years ago -- 700 years
                  before Europeans first saw North America's fifth highest peak -- Mexico's second highest
                  at 5,465 meters (17,930 feet).

                  Hernando Cortes saw the mountain erupt in 1519 on his way to conquer Mexico for the
                  Spanish. He sent expeditions to the top, and Francisco Montano in 1522 became the first
                  known European to ascend the peak. Diego de Ordaz, a Cortes lieutenant and sometime
                  rival, claimed to have reached the summit in 1519, and some reports give credence to his
                  claim. Montano, however, can lay claim to the first European trip inside Popo's crater. His
                  men lowered him by rope 122 meters (400 feet) to gather sulfur from the crater walls.

                  Aztec artifacts and structures have been found on the sides of the mountains, but
                  the Aztecs left no record of an ascension to the summit.

                  Mexico's National Disaster Prevention Center has
                  detailed what is known of Popo's eruptive life.

                  About 23,000 years ago: A large Mount St.
                  Helens-type eruption

                  About 14,000 years ago: Large eruption spews
                  ash and pumice

                  14,000 to 5,000 years ago: Multiple eruptions, at
                  least four classified as "large."

                  3,000 B.C.: Large eruption

                  200 B.C.: Large eruption

                  800: Large eruption

                  1354: Minor eruption

                  1519: Moderate eruption

                  1539 to 1549: Moderate eruption

                  1663: Moderate eruption

                  1720: Mild eruption

                  1919-1927: Moderate eruption. Several deaths recorded inside the crater, where
                  workers were extracting sulfur. Small lava dome grew on crater floor

                  1994 to present: Moderate eruption. Small lava dome fills a fifth of crater. Five
                  killed near crater rim in 1996. Scientists say past six years of activity similar to
                  1919-1927 eruption. Activity has been on a steady increase for most of 2000,
                  particularly since an explosion in early September sent ash into the air for 25
                  minutes. The area around the volcano went on heightened alert after an October
                  31 eruption. Evacuations began December 16.