He treated that secret like Pandora's box.

According to Greek mythology, it is said that when Pandora's box is opened, all evils are released.

When he opened the supernatural 'box', an unknown power was released.

The Ark of the Covenant is a sacred box described in the Old Testament.

He is a box believer, so he buys a new game as soon as it comes out.

He put money into the offertory box.

Where is my toolbox?

There are already many votes in the ballot box.

He put the matchbox in his pocket.

He made a plan to build an ark.