The corridors of power
Definition 1 of 1
Pro Tip 1/3Metaphorical Space
The phrase represents a metaphorical space, not actual hallways. 
Her new position put her in the corridors of power, where she influences company policy.
Pro Tip 2/3Influence and Authority
'Corridors of power' implies a place where people possess authority and make impactful decisions. 
Only a select few can navigate the corridors of power effectively.
Pro Tip 3/3Not Always Visible
The activities in the corridors of power can be secretive or not obvious to outsiders. 
Journalists try to uncover what happens behind the scenes in the corridors of power.