I may be mistaken but I was taught that the Constitution was unlike other US laws as it is the foundational law - i.e. the highest law in the land, superseding

I may be mistaken but I was taught that the Constitution was unlike other US laws as it is the foundational law - i.e. the highest law in the land, superseding all other laws. Any law that violates the Constitution is unconstitutional and can be challenged on that ground so as to be stricken down as null and void. What am I missing?