Meaning: the offices of the powerful leaders.

Example:
As personal adviser to the Prime Minister, he thought he’d get his foot inside the corridors of power.

Meaning: stop needing somebody else to look after you and start acting independently.

Example:
In order to achieve true independence, developing countries must cut the cord and stop asking for financial aid from the developed countries.

Meaning: be very calm and relaxed, particularly when it's astonishing. Undisturbed by temperature or any action.

Example:
1. There he stood, cool as cucumber and totally oblivious to the violence that had shattered the very fabric of the society.
2. This is too hot today but looking as cool as cucumber.

Meaning: to gain full satisfaction. When the limit is up to the requirement of the other person

Example:
1. The man ate food at the buffet to his heart's content. He seemed really happy as he left for home.
2. I used to keep giving him a piece of my mind regularly which he would not pay much heed to, so today I yelled at him to my heart's content.