"Not since the discovery of gunpowder has the world wondered over the ability of man to create such an agent of destruction," spake the narrator of the Naval Photographic Science Laboratory's Project Crossroads film, the source of the images and quotes on this page. The date was July 1, 1946. One short year earlier, Oppenheimer and friends had made atomic warfare a reality with the Trinity tests. A month after that, the whole world found out about it when atomic bombs were dropped on Hiroshima and Nagasaki, bringing the war with Japan to an astonishing end. By 1946, the world was already a very different place. "In this 20th century world of atomic power," the Crossroads film narrator rambles in a propagandistic call-to-arms, "man is fully aware that he cannot assume an attitude of indifference to this new elemental force that he discovered and must prepare against." Of course, part of that preparation entailed more atomic bomb tests. In December 1945, President Truman issued a directive to conduct nuclear weapons tests "to determine the effect of atomic bombs on American warships." To that end, an Army/Navy Joint Task Force was deployed to Bikini Atoll to carry out the world's fourth A-bomb detonation. Bikini Atoll was chosen as America's new nuclear proving ground because of its relatively isolated location away from air and sea routes. Of course, it was inhabited at the time. In February 1944, U.S. forces had wrested the Marshall Islands from Japanese control, after one of the most violent battles of World War II. Just two years after this terrifying clash, Commodore Ben H. Wyatt, military governor of the Marshall Islands, traveled to Bikini on a mission. Following church one Sunday in February 1946, Wyatt assembled the Bikinians to ask them to abandon their homes "temporarily" so that the United States could test atomic bombs "for the good of mankind and to end all world wars." King Juda and the people of Bikini were confused and distressed as they discussed the request. In the end, King Juda told Wyatt, "We will go believing that everything is in the hands of God." In March 1946, the 167 inhabitants of Bikini were transported on a Navy LST landing craft to Rongerik Atoll 125 miles to the east. Tons of camera equipment and more than half the world's supply of motion picture film was brought in to document the tests and the movement of the Bikinians from their atoll. Not a single frame of the Bikinian exodus appears in the Navy's film on Project Crossroads. The islands of Rongerik were previously uninhabited because of their inadequate size -- about one sixth the size of Bikini Atoll -- and inadequate water and food supplies. The people of the Marshall Islands even had a cultural taboo against living on the island: according to a traditional belief, the atoll was inhabited by evil spirits. The Bikinians were given only enough food to last a few weeks when they disembarked on Rongerik, and the islanders found out the hard way that the coconut trees and local food crops yielded little fruit in comparison to the bountiful trees of Bikini. Compounding the problem was the dearth of edible fish in Rongerik's lagoon. Within two months, the Bikinians began begging U.S. officials to move them back to their home. But by then, more than 42,000 military and civilian personnel had descended on Bikini to begin preparations for Operation Crossroads, turning the atoll into a claustrophobic hive of feverish activity. As the people of Bikini literally began to starve, thousands of experimental test animals were prepared for scientific slaughter at Bikini. Ever since then, according to the Bikini Atoll Web Site, "The history of the Bikinian people from that day has been a story of their struggle to understand scientific concepts as they relate to their islands, as well as the day-to-day problems of finding food, raising families and maintaining their culture amidst the progression of events, set in motion by the Cold War, that has been for the most part out of their control." In the years to come, the people of Bikini would find themselves repeatedly relocated from island to island, subject to the whim of the U.S. atomic weapons program. Many more nuclear bomb tests would be conducted at Bikini, including the first hydrogen bomb test during Operation Ivy and additional thermonuclear weapons tests during Operation Castle. When the first test was conducted at Bikini in July 1946, atomic weapons researchers were more interested in the effects of the bomb than the bomb itself. To this end, "everything from canned milk to tanks" was exposed to the "Test Able" blast, including 5,400 pigs, mice, goats and sheep which were used "to substitute for military personnel" in the tests. "Some were shaved so that the effects of heat and radiation on their skin could be observed, and the results applied to the design of protective clothing," the narrator tells us. Ah, progress. According to President Truman's orders, a fleet of derelict and obsolete ships were deployed around Ground Zero. Among the various cargo vessels and cruisers were the aircraft carrier Saragota, the U.S.S. Nevada, and, the narrator tells us, the "Jap battleship Nagato." The narrator does not mention that the Nagato was the former flagship of the Japanese Imperial Navy. Perhaps to the film's intended audience, the point was obvious. On July 1, 1946, the B-29 Dave's Dream dropped the Test Able device -- a bomb roughly equal in firepower to "Fat Man," the Nagasaki bomb -- onto the target array. As the mushroom cloud rises above Bikini Atoll, the Project Crossroads film narrator chants, "Although a beautiful sight, this swirling, boiling mushroom cloud is certain death to any living thing which approaches too close to its edge." Several B-17 and F-6F drone aircraft were flow into the cloud to collect radiation samples. One drone momentarily disappeared as it was raised 6,000 feet in the updraft while passing through the smoke column. Not to worry, the film narrator informs us. As the cloud began to disperse, "one thing was certain: the dangerous radioactive particles in the cloud had become so scattered that no longer was there any danger to the surrounding area." Truthfully, though, that was yet to be seen. Test Able was an air drop; atomic weapons researchers also wanted to try something new with Operation Crossroads -- an underwater detonation. The target ships which weren't sunk during Test Able were assembled for Test Baker, which took place on July 25, 1946. The people of Bikini were at this point terribly concerned about the fate of their island, so King Juda was allowed to visit the island and witness Test Baker. As Juda is shown boarding the command ship, the film narrator says, "It was he who unselfishly gave his island to the United States in order that these experiments could be conducted." The narrator tells us that he "displays a marked interest in the proceedings." And that's about all we hear from King Juda. After his visit to Bikini, Juda reportedly returned to Rongerik and told his people that their island was still intact and basically looked the same, and that the trees were still there. It was trifling compensation for the hardship and danger which the people of Bikini would endure in the decades to come, as America's fear of Communism fueled increasingly ambitious nuclear weapons tests. The Test Baker bomb -- also roughly equivalent in power to the Nagasaki bomb -- was detonated just under the surface of the water, sending a wall of irradiated steam hundreds of feet into the air, engulfing the target fleet. Heavily laden in "hot" fission byproducts, many of these vessels sank off Bikini's shore. Oddly enough, they say the fishing is great there now. NEXT: Buster/Jangle -- The Nevada Tests Begin