Mount Rainier is a ticking time bomb that could dwarf the 1980 eruption of Mount St. Helens, sending massive lahars and mudslides toward the Seattle-Tacoma metropolitan area.

The largest volcanic eruption of the past two million years occurred on the Indonesian island of Sumatra some 75,000 years ago. The impact from the supervolcano Mount Toba decimated the local habitat, but gas, ash and debris from Toba made their way around the planet and formed a shield in the atmosphere that deflected the sun's warming rays. Temperatures plummeted and the planet was thrown into a volcanic winter and may have even pushed the planet into an ice age. 3-D computer animation will recreate the storm and unveil how this one volcano could have brought humanity to the edge of extinction.

Methane gas precipitates out of the Earth's crust but is easily diluted in the air and in the oceans. Yet, according to one scientist, certain oceanic conditions could trap the gas in regions with low water circulation and build up extreme pressure. Once these areas are disturbed, the gas would blow out of the ocean in powerful jets. If they ignited before diluting, the explosion could cause widespread devastation. The scientist also posits that a similar event caused the Permian extinction.

The New Madrid Fault could reawaken at any time and destroy St. Louis, Missouri and Memphis, Tennessee, like the New Madrid Earthquake of 1811-12.

Yellowstone National Park lies on top of a magma chamber that is 35-miles wide, waiting to erupt. (For further information, see Yellowstone Caldera.)

Cumbre Vieja, a volcano on the island of La Palma in the Canary Islands, off the northwestern coast of Africa, may potentially collapse in the future. If it does, a massive tsunami will be headed right for the East coast of the United States, threatening major cities like New York, Boston, Baltimore, and Miami.

Exploring the possibility that a hypercane (a theoretical super hurricane) may have hit Earth billions of years ago and destroyed most of the life on the planet.

The possibility of a tornado hitting downtown Chicago is the scenario. Included is an examination of the 1967 twister that hit the suburb of Oak Lawn.

The United States faces a potential tsunami threat that mirrors the catastrophic Indonesia tsunami of 2004. Just west of the Oregon coast lies the Cascadia subduction zone where the Juan de Fuca Plate is moving under the North American Plate. A major earthquake here could displace enough water to cause a massive wave to impact along the west coast.

An asteroid hitting the Earth off the coast of Los Angeles is the scenario. Included: the theory that an asteroid strike may have been responsible for the extinction of dinosaurs.

Chemistry has changed our way of life. From the gasoline in our cars, to the quality of water we drink, to the furniture we sit on. But with modern industry come hazards and risk, including potentially the explosive release of a dangerous chemical. Could a Toxic Cloud be the next mega disaster?

A comet is imagined to strike the Earth and cause major devastation.

Could the island nation of Great Britain have once been connected to Europe by land? Listen to a new theory and evidence which suggests that the English Channel was created by one of the largest floods ever. Did a violent storm re-shape the European continent? Might this happen again? Dramatic 3-D animations recreate what this prehistoric mega storm may have looked like and unravel the mystery behind the creation of England.

The possible effects of extreme climate changes around the world in a short period of time are examined. Included: how drought altered the Mayan civilization.

The 1883 eruption of Krakatoa was one of the deadliest natural disasters in recorded history, claiming over 36,000 lives by the tsunamis it triggered. Another volcanic eruption at Krakatoa, now called Anak Krakatau (meaning "Child of Krakatoa" in Indonesian), could spell curtains for Indonesia.

How a major tornado would impact Dallas is examined by studying the effect of a twister that struck Oklahoma City on May 4, 1999, killing 43 people and causing $1 billion in damage.

A Category 3 hurricane hitting New York City is the scenario. Included: a history of hurricanes in the Northeast; and the origins of such storms.

The Hurricane Katrina disaster is studied as a model to examine what might happen if Sacramento's levee system failed and a similar tragedy resulted.

Modern dams are marvels of engineering but after decades of neglect the U.S. infrastructure is in crisis and by 2020, 85% of U.S. dams may be near their breaking point. When the South Fork Dam near Johnstown, Pennsylvania gave way in a storm in 1889, killing 2200 people, it was the worst disaster in U.S. history. Today, with millions of Americans living nearby massive dams, the result of a failure could be catastrophic.

This special-edition episode examines what happened in the 1906 San Francisco earthquake and its effect on San Francisco and looks at the destruction if it were to happen again today.

In AD 79, Mount Vesuvius buried Pompeii and killed 5,000 people. The volcano is quiet at the moment, but the only consistency in Vesuvius' eruptive history is a lack of consistency. The danger zone that surrounds the volcano includes the city of Naples and its one million residents; another two million people reside nearby. Scientists know that when Vesuvius erupts again they won't have much warning and another major metropolis will be destroyed.

In 6,000 BC, 8,000 years before the 2004 Indian Ocean tsunami, a paleotsunami whose waves reach taller than the Statue of Liberty allegedly was generated by a landslide from Mount Etna and ravaged the coasts of the Mediterranean Sea, devastating ancient villages and killing untold numbers. A team of scientists pieces together evidence of this megatsunami and reveals the face of this ancient tsunami for the first time. 3-D computer generated animation recreates the massive waves that may have changed the course of history.

Trends indicate that a major drought event is looming in the not-too-distant future. In as few as three decades we could experience conditions that would make the Dust Bowl of the 1930s seem like an oasis. Efforts to conserve, while admirable and desperately necessary, may already be too late. The episode projects a scenario seventy years into the future in which a twelve-year drought leaves the United States unstable and economically depressed. Western cities are abandoned, states clash for dwindling water supplies and society devolves into a battle for survival.

Every few seconds, a supernova emits jets of deadly gamma rays somewhere in the galaxy. If one of these gamma ray bursts should happen sufficiently close to the solar system, all life would perish.

About 8,000 years ago, rain squalls had global oceans surging. The oceans rose above all of the earth. When the flood was over the Mediterranean Sea had claimed a landmass twice the size of Ireland. This prehistoric mega-storm was the greatest natural disaster in human history. 3-D computer animation will recreate what this lethal flood may have looked like.