With its extreme conditions, Antarctica has historically been inaccessible to humans. Thus, unlike much of the rest of the world, the continent was not subject to disputes over territory. With the technological advances of the 1900s, however, access improved, and scientists were eager to research the area. When a dozen countries established research stations in Antarctica—with nine making claims on specific regions—experts became concerned that territorial conflicts would arise and ultimately restrict research. In response to this potential threat to scientific progress, the twelve countries negotiated the Antarctic Treaty. Among other stipulations, it restricted countries from claiming land, banned military activities and nuclear explosions, and required that countries share their research results with other countries' scientists. The Antarctic Treaty was ratified on June 23, 1961. The agreement has successfully ensured continent-wide scientific cooperation. What is the main idea of the passage?