Robert Montgomery: Narrator (voice) (as Comdr. Robert Montgomery, U.S.N.R.)
Robert Taylor: Narrator (voice) (as Lt. Robert Taylor U.S.N.R.)
Van Heflin: Narrator (voice) (as Lt. Van Heflin, A.A.F., Ret.)
James Forrestal: Himself (as James V. Forrestal)
Chester W. Nimitz: Himself
Rear Admiral Richard E. Byrd: Himself (as Admiral Byrd)
Richard Cruzen: Himself (as Admiral Cruzen)
Robert S. Quackenbush: Himself (as Captain Quackenbush)
George J. Dufek: Himself (as Captain George Dufek)
Paul A. Siple: Himself (as Dr. Siple)
Charles W. Thomas: Himself (as Captain Thomas)
Richard E. Byrd Jr.: Himself
Vernon D. Boyd: Himself (as Captain Boyd)
Charles A. Bond: Himself (as Captain Bond)
David E. Bunger

This film documents the largest expedition ever undertaken to explore Antarctica. The expedition, code named "Operation High Jump," was made by the U.S. Navy and involved 13 ships (including one submarine), 23 aircraft, and about 4700 men. The film was shot by photographers from all branches of the U.S. military. One purpose of the expedition was to explore and photograph several thousand square miles of inland and coastal areas that had not been previously mapped. Additionally, military planners wanted to evaluate whether military troops could successfully perform against an adversary in such an environment

In the summer of 1946 Secretary of the Navy James V. Forrestal approved the largest naval task force, 13 ships and 4,700 men, since the end of the Second World War to sail from Norfolk Virginia to the cold and ice capped seas of the Antarctic to map that unknown and frozen continent as well as monitor the vast and untapped natural resources hidden under it's frozen surface.

The film "The Secret Land" is a documentary narrated by actors Robert Montgomery Robert Taylor and Van Haflin about that fabled expedition call Operation Highjump and the men who were on it. Who suffered through it's deadly cold winds ice flows and the dreaded coming of the Antarctic winter that may well have spelled doom to all of those sailors and merchant marines on that perilous expedition.

Led by Admiral Richard E. Byrd and Rear Admiral Richard H. Cruzen Operation Highjump did what it set out to do, by mapping some 1.3 million square miles of the unknown Antarctic continent. There also was a number casualties among the ships and men on that voyage. The most noted was the USS Sennet a submarine that was crushed in the ice off the US base Little America.

Leaving from the US port in Norfolk to the southern most part of the Pacific Ocean to Scotts Island and Little America on the Antarctic land mass. Aircraft carrier USS Philipine Sea the flag ship of task force 63, Operation Highjump, had on it's deck six giant RD4 supply planes who, with Admiral Byrd aboard, flew over the frozen wastes of that continent and photograph it.

In the end the expedition was considered to be a major success but over the years it has all but been forgotten by the American public but It's good to see that the movie "The Secret Land" is still around and is being broadcast periodically on TCM to rekindle interest in that major post WWII event.

Even though Operation Highjump was conducted over fifty years ago many of the photographs and documents on that expedition are still classified and there's the strange explanation of Admiral Byrd's missing three hours, when he flew over the South Pole in February 1947. Having the American public told that Byrd's RD4 had to jettison most of it's equipment to avoid losing altitude and slamming into the dangerously high Antarctic mountain ranges, that in some places are as high as 20,000 feet, that had communications cut off between him and the US base on frozen Antarctic coast. That explanation didn't wash with a lot of the people who listened to the Admirals radio broadcast as he flew over the pole.

The broadcast by Admiral Byrd suddenly went dead for a number of minutes and there are those who think that it was done on purpose, by the US Navy, to keep the American public from knowing just what he saw there.

There was one fantastic discovery by the Byrd task force that didn't escape the attention of the American media and public as well as the lens of the movie camera. That was the discovery, off the Shacklenton Ice Shelf in Wilkes land, of a place later named the Bunger Oasis.

Flying over the ice and snow US Navy Let. Commander David E. Bunger spotted filmed and landed on this 300 square mile patch of land with tricolor fresh water lakes that were totally ice-free right in the middle of the blistering cold and freezing Antarctic! The lakes in the Bunger Oasis were the colors, red blue & green, of the vast amount of colored algae in them and even now, over a half century after the Bunger Oasis' discovery, nothing in the world of science has been able to explain it.

Synopsis

In 1946, the U.S. Navy launches "Operation Highjump" to explore and map the Antarctic region and, in the process, test men, ships and equipment against the harsh climate. Chester W. Nimitz, Chief of Naval Operations, directs the expedition. Three groups make up the expedition: The central land-plane group, headed by Rear-Admiral Richard E. Byrd, will explore and map the interior from a base in Little America, while two other groups will explore and map the eastern and western coasts. The teams must finish their work before the end of the brief Antarctic summer. In addition to scientific equipment and other supplies, the ships carry sled dogs to provide land transportation.

At the equator, men and dogs who have never crossed the equator are initiated in humorous King Neptune ceremonies. When strong storms hit the ships in the southern hemisphere, many sailors are injured and several seaplanes are lost. The rough seas prevent the central group from landing at Scott Island, but despite this setback, the men onboard celebrate Christmas with a traditional dinner and gifts. The central group now depends on an icebreaker to cut a path through the ice pack in the Ross Sea to the Bay of Whales and the base at Little America on the Ross Ice Shelf. Meanwhile, the western group has reached Peter Island. From there, seaplanes scout the coast, where they find explorer Robert Scott's former camp. The progress of the central group is hampered by ice, and the submarine accompanying the ships is caught between two ice flows. The icebreaker returns to free the submarine, which is sent home.

While the western group waits for the icebreaker's return, they observe and capture for further study penguins, seals and other Antarctic wildlife. When the central group reaches Little America, the explorers unload their equipment and, making use of the twenty-four-hour summer daylight, quickly build a tent city and airstrips. Admiral Byrd flies in on the first airplane, which lands perfectly, but the remaining planes must take off at night in order to beat an approaching storm. After the blizzard clears, ice is cleaned off the planes, and a man crawls down a shaft to an earlier base buried under the snow. The cold, dry air of Antarctica has perfectly preserved the supplies that were left behind. While mapping expeditions fly over the land, divers test cold-water survival suits in the frigid ocean. On flights from their base in the Bellany Islands, the eastern group spots Mt. Aramis, the only active volcano near the South pole, and near the Shakleton Ice Shelf, the explorers discover 500 miles of snowless land heated by warm water lakes, which they name Bunger's Oasis. The short summer is ending, and the fleet near Little America is becoming frozen in the ice.

After the fleet is freed by an icebreaker, it departs, leaving behind Byrd and some volunteers to continue explorations by air. During the eastern group's mapping of the Phantom Coast, mountains made of coal are discovered. A crew is lost during one flight, and after a search of two weeks, the survivors are found. Three men die in the crash and one, badly burned, loses his legs to frostbite. The icebreaker returns to pick up Byrd and his men, and the successful expedition returns home, having learned much about this largely unknown territory.