blockchain – how large a block can grow?

I was looking for a blockchain exchange but I didn’t see so I am posting this in Bitcoin group. Apologize if it’s too na├»ve.

I’ve started to learn about bitcoin and blockchains. I don’t understand how the whole network transactions can be assembled into blocks and then all these blocks validated and broadcast. Is that efficient? It’s basically a block that grows in size every second. How this large data is going to be processed, stored and broadcasted efficiently? I am sure I’m missing something as this is obvious.