A five-minute stop that means everything. Go at dawn, when it's empty.
The Brandenburg Gate is Berlin's hinge of history — Napoleon, the Wall and reunification all ran through it. It's a five-minute stop that means everything and, in daylight, looks like a crowded selfie backdrop.
As a photo stop with real historical weight, yes — five minutes at dawn is plenty.
Yes — it's free to enter.
Come at dawn or after dark, when it's lit and nearly empty, because the emptiness is the point given what this square used to be.