I think he may be secretly building a B ark.

"They are building secretly on their militant cells across the country."

North Korea is in the business of secretly building nuclear bombs.

Further, Earth is secretly building ships again, and will launch a new fleet if it can buy enough time.

It must have been secretly built when the old house was first put up, two or three centuries ago - with a secret way in.

In 2005, a second stage was secretly built in an adjacent field.

He is secretly building an automaton and hopes it will promote him to his own business.

Iran is secretly building nuclear bombs with Russia's help.

They secretly built this place after he was elected.

According to recent rumors, Facebook may be secretly building a software platform for smartphones of the future.