He also warned against the danger of the wildlife trade being driven underground, where it could not be monitored.

"The result," he said, "is people are forced to operate outside the law, and so an economy producing billions of dollars has been driven underground."

Now, he said, "It's more private and out of sight; it's been driven underground."

Life on this planet has been driven underground.

In the 1950s, as the party was driven underground, it began supporting major workers' strikes around Brazil.

Children's written communication had not been driven underground.

Now there is a war on and we've been driven underground for eight or nine months.

With the "industry" driven underground, the opportunities for exploitation of girls would be greater than ever.

In other words, grown-up philosophers are those whose curiosity has not been driven underground.

The film, like the movement, was driven underground.