Smithsonian Channel

The discovery of a submerged, 9,000-year-old stone circle may reveal the mysterious origins of Stonehenge.

Learning how displaced artifacts spark fresh investigations and rewrite timelines; unearthing a forgotten tragedy in a remote mountain lake in India, checking out footprints that change human migration stories; reopening an ancient cold case.

The first great empire of the Akkadians, led by Sargon the Great, dominated the Fertile Crescent, replacing the Sumerians and extending its influence as far north as Syria and south as Oman.

The discovery of a submerged, 9,000-year-old stone circle may reveal the mysterious origins of Stonehenge.

A new performance center with a tent-like glass-and-steel lobby tests engineers in Kansas City; two twisting apartment towers make heads spin in Ontario.

In Florida, Mike tackles one of the dangerous jobs on the planet, commercial diving; he helps a specialized team keep waterways safe; fixing construction site leaks and removing dangerous structures, all while hurricane season is in full swing.

The St. Lawrence River is one that forged North America, allowing ships to traverse the continent; the adventure begins in Canada's first capital city of Kingston and near Canada's second-largest city of Montreal.

Explores strongholds abandoned by their architects; a lost city in the Amazon jungle; a desert fortress made by humanity's most notorious empire; explores a city of identical castles; examines a Greek isle's bloody history from the air.

Jeremy Birch takes on a salvage to raise a vessel with a concrete hull; it's been in the Fraser River for a month, collecting silt and mud, adding 30 tons to its deadweight.

The St. Lawrence River is one that forged North America, allowing ships to traverse the continent; the adventure begins in Canada's first capital city of Kingston and near Canada's second-largest city of Montreal.

Explores strongholds abandoned by their architects; a lost city in the Amazon jungle; a desert fortress made by humanity's most notorious empire; explores a city of identical castles; examines a Greek isle's bloody history from the air.

Jeremy Birch takes on a salvage to raise a vessel with a concrete hull; it's been in the Fraser River for a month, collecting silt and mud, adding 30 tons to its deadweight.

Follow the meteoric rise of the Macedonian conqueror who seized Egypt and built an empire that stretched from Europe to Asia; find out how founding the city of Alexandria and becoming a pharaoh transformed Alexander's life before his death at age 32.

Part 2/6. Uncover the secrets of the Old Kingdom ruler who revolutionized architecture alongside his vizier, Imhotep; piece together the mysterious life of the very first king to build a step pyramid in the heart of a grandiose and complex burial site.

Ramesses II reigns for 66 years and builds monuments and temples.

Delve into the history of the Fourth Dynasty monarch responsible for one of the great pyramids; examine the tyrannical reputation of this ancient leader and decipher the complex strategies he used to guide such a massive building project.

Part 5/6. Chart the turbulent reign of a brilliant strategist who allied herself with powerful Roman leaders in the hopes of saving her kingdom; examine the battle against Octavian that ended three millennia of Egyptian history and sealed Cleopatra's fate.

Part 6/6. Unearth the dramatic final days of the Twentieth Dynasty's great warrior king, Ramses III; view a rare judicial papyrus that recounts the story of an assassination plot hatched in the royal harem; see what the monarch's mummy reveals today.

Part 1 of 2: Travel the length of the Nile, from Cairo to Aswan, as Tony explores tombs of every shape and size; find hidden treasures, hunt for a lost pyramid and find out what newly discovered mummies can tell about ancient Egyptian history.

A look at how the post-war period and the Cold War unfolded high up in the North; recently published archival material helps to shed light on post-war events in the Arctic.

The inside story of how the AH/MH-6 evolved over the decades to become an irreplaceable aircraft for the U.S. Military.

There are many stories behind the 1940 Battle of Britain, like pilot Bill Millington who sacrifices himself to save civilians.

A look at how the post-war period and the Cold War unfolded high up in the North; recently published archival material helps to shed light on post-war events in the Arctic.

The inside story of how the AH/MH-6 evolved over the decades to become an irreplaceable aircraft for the U.S. Military.