be like Fort Knox

Airports and airplanes are like Fort Knox compared with other forms of transport.

And as far as security is concerned, this place is like Fort Knox.

It's like Fort Knox your house.

I carried them past security guards, R&A officials; it was like Fort Knox.

Erm and the place is like Fort Knox at the moment, cos it's got double sort of ten lever locks on every door, because somebody was pilfering from there,