Passed Pawns

A passed pawn can be very dangerous even one passed pawn could be dangerous, the connected passed pawns are even more dangerous. If a passed pawn reaches the seventh rank (or 2nd for black) bet you can't stop the, well you can but it's hard, here take a look at this game where one player has a passed rook pawn

Now, after seeing that game you know how dangerous passed pawn is, and that's not a connected passed pawn. A connected pawn could overwhelm a rook himself, even with only two connected pawn could overwhelm the rook without any help, only two of them.

Connected passed pawn is nearly impossible to stop without losing material. So the pawns may be weak but they are strong together here is a quote about passed pawn by Aron Nimzowitsch 

“The passed pawn is a criminal, who should be kept under lock and key. Mild measures, such as police surveillance, are not sufficient.” – Aron Nimzowitsch 

that means the passed pawn are strong and we need to do big things to stop it, you can't stop a passed pawn with only one rook, add another one

 passed pawns are really important on the endgame because there are less pieces to stop it, so just try to kill the passed pawn anywhere it was, believe me, or you gonna lose from the 1-point piece; some time I do lose from a passed pawn because of not holding it lol. So just never underestimate the pawn