Why have there been no major exploratory expeditions for the past fifteen years?

In September 1998, another team of divers made a major expedition to the wreck.

His first major expedition was in 1596, when he sailed to Africa.

In 1924, he undertook the first of his two major linguistic expeditions.

"She's not up to a major expedition yet," he replied.

He personally organized and led more than 15 major expeditions to extreme parts of the world.

He led at least four major expeditions during his life.

This will not be a major expedition or effort.

For 1755 a major expedition was planned against the French in America.

He spent the rest of his life preparing for major second expedition.